DNA - When Cousins Marry: Pedigree Collapse vs Endogamy
Vložit
- čas přidán 2. 07. 2024
- When cousins marry, it can create confusion when looking at DNA centimorgans and your genetic relationships. In this episode we explore the differences between Pedigree Collapse and Endogamy in your DNA results. This is an interview with guest Diahan Southard. Learn how to spot Pedigree Collapse in your own family tree.
📃 There is a HANDOUT for INFO ACCESS level Channel Members. Channel Members can find the handouts in the Community Tab on the CZcams channel. Look for the words HANDOUT in the blog posts.
📃 This HANDOUT can be purchased separately without membership here genealogytv.org/product/hando...
👉 JOIN the CHANNEL MEMBERSHIP at the Information Access level to get the handout. czcams.com/users/GenealogyTVjoin
👉 Subscribe to Genealogy TV on CZcams
bit.ly/2Riym67
✨Your DNA Guide (book) by Diahan Southard
amzn.to/2QaV93h
✨Diahan’s website
www.yourdnaguide.com/
🧬OTHER DNA VIDEOS🧬
🔴 AncestryDNA Grouping Cousin Matches: Clarified
• AncestryDNA Grouping C...
🔴 Organizing DNA Cousin Matches using Excel Spreadsheets
• Organizing DNA Cousin ...
🔴 Grouping DNA Cousin Matches on Ancestry
• Grouping DNA Cousin Ma...
🌱 Subscription or FREE TRIAL to Ancestry.com (affiliate)
bit.ly/3tNLCwG
📰 Subscription to Newspapers.com (affiliate)
bit.ly/2RiydzB
TIMING
0:00 Intro
1:19 Genetic Genealogist Diahan Southard
1:46 Pedigree Collapse vs. Endogamy
3:45 DNA and Recent Common Ancestors
3:59 What is Endogamy?
4:28 Recognizing endogamy in DNA matches
6:06 Geography and Endogamy
7:00 23andMe, Ancestry, MyHeritage DNA Algorithms for endogamous groups
8:01 FamilyTree DNA for endogamous groups
8:28 Ancestry.com - Timber
8:54 Identical by State vs Identical by Descent
9:40 The Timber Algorithm - how it cuts down your matches
10:37 Example: Diahan’s Grandmother
13:11 When endogamy gets in the way
13:40 MyHeritage Chromosome Browser
14:38 Small Town Endogamy
15:16 Can we find out who the DNA comes from?
15:45 What kind of DNA to look for
16:35 Your DNA Guide
17:32 Is pedigree collapse easier to solve?
17:53 Multiple relationships
18:17 How many events?
19:02 Who will see pedigree collapse?
19:41 What 2 relationships do these cousins have?
21:04 Calculating expected shared DNA
21:53 Using the Shared Centimorgan Project
22:30 Looking for Biological Parents
23:20 Exploring all possibilities
24:43 Using DNA to rule out endogamy
26:47 YourDnaGuide.com
27:00 Free downloads
27:42 Follow Diahan's Work
28:14 You can do DNA
28:36 Research matters
28:58 Handout
29:19 Outro
* * *
❤️BECOME A GENEALOGY TV CHANNEL MEMBER and help support Genealogy TV. Click the link to learn about the Perks of Membership.
czcams.com/users/genealogytvjoin
❤️ NEED HELP? Join the "Genealogy TV Insiders" coaching group or sign up for private coaching.
genealogytv.org/coaching-opti...
❤️ TIP JAR - If you wish to help support Genealogy TV, please consider becoming a Patreon member. Click link below to donate to help keep more videos coming. Thank you!
/ genealogytv
🆓 FREE eBOOK - How to Trace Your Family History for Free.
mailchi.mp/c5db92ec5df1/genea...
▶️ SUBSCRIBE To Genealogy TV on CZcams at
czcams.com/users/genealogytv?...
✅ Genealogy TV WEBSITE
genealogytv.org/
✅ Genealogy TV on FACEBOOK
/ genealogytv
✅ SIGN UP For GENEALOGY TV NEWSLETTER
bit.ly/3eKEWuQ
🌳 FOR ALL PLAYLISTS on Genealogy TV
bit.ly/3bpIlNH
I am a fanatic for genealogy, family history and DNA to research my American ancestors . I am a professional genealogist; I teach research skills and records research. The best videos on “Genealogy TV” (CZcams) are about learning research notes, logs, staying organized, genetic genealogy, finding missing ancestors, and where to find family history records. Learn genealogy for free and how to research on Ancestry.com, FamilySearch.org, MyHeritage.com, FindMyPast.com, FamilyTreeDNA, AncestryDNA, 23andMe, Wiki Tree, Geni, National Genealogical Society, National Archives, State Archives, local family history rooms, genealogical and historical societies genealogybank.com, Chronicling America, Newspapers.com, Newspaper Archives.com, Fold3, Archive.org, Internet Archive, Wayback Machine, Digital Public Libraries, National Archives, Google, Google Books, Google News, Facebook for genealogy groups, and the very best genealogy websites and resources.
Other CZcamsrs are The History Guy, Ancestral Findings, Family History Fanatics, Geneavlogger, Legacy Tree Genealogy, Genealogy TV (of course), Ancestry, FamilySearch, Useful Charts, Dear Myrtle, and 23andMe.
Music Credits for Song on Word Tree Open
Circus Waltz Kevin MacLeod (incompetech.com)
Licensed under Creative Commons: By Attribution 3.0 License
creativecommons.org/licenses/b...
Are you working on sorting out your DNA relatives? Connie has more videos that can help! 😊
🔴 AncestryDNA Grouping Cousin Matches: Clarified
czcams.com/video/YOGarVcxLRQ/video.html
-Diana, GenealogyTV Team
I've sorted and then sorted again in some instances. I doing this on my wifes side of tree. She was adopted and didn't know the parents. So she is a half to almost everything. I think I understand the charts and then something doesn't look right and a second guess myself.
I understand. Been there. Make sure you’re combining traditional genealogy research with your DNA hypothesis. Be careful of confirmation bias.
My Wisconsin mother had 75 first cousins. So. my siblings and I simply avoided the entire Midwest.
Oh my god how is 75 even possible?
I'm with you I can't date anyone from Wisconsin either. All these ancestors having affairs I don't know all of my relation here lol...
So I should avoid that area too since my family on a few generations are from there too. 😂😂😂
Why would you avoid the area?
LoL, I have same situation. Grandma had 12 kids . Each kid had 6-9 kids each. Most have stayed in Milwaukee.
Great video. My maternal grandparents were first cousins. I always say my family tree doesn’t branch.
I was on a bus going from Philly to NYC and hitting on a girl who asked where I was from. When I told her she asked if I knew her cousi...... yep, he was my 2nd cousin too :(
That cousin could be her 1st cousin by her parent who is unrelated to you. And ditto, your 2nd cousinship could be via different bloodlines. Lastly, in USA in many states 1st and 2nd cousins may marry. King Henry 8 when in 1530s he broke with the Church of Rome, which had defined incest as within 3rd cousinship, newly legitimized for Anglicans first cousin marriage. Of course, theologians' opinions on endogamy can differ from geneticists'.
I'm 98% Finnish and this is a major issue in Finnish genealogy. At least in rural areas with lower populations, like much of Ostrobothnia (Pohjanmaa). My maternal grandparents we're second cousins once removed.
This is when I would stick with traditional genealogy research... and not so much DNA.
DNA can still be used, but only for finding names and trees. Then it'd a matter of matching the trees.
Btw, those finns emigrated to Sweden and those are my ancestors. And same issue there, people did not really move around for hundreds of years.
I don't have a family tree, I have a twisted ficus. On my mother's side of the family, I have one 5th great-grandfather who had at least four relationships and I descend from him five different ways via children from three of the four relationships. I can have a family reunion in the shower. I had to use the DNA to figure out which woman was the mother of which child. I expected Maury Povitch to announce "You are the mother!"
Ha ha, a twisted ficus - I love it. That's my mom's side of the family.
Lol
Too funny
@@debbiezipoli3768 Mom's family is eight generations SE Kentucky Appalachian mountains with many of the same families traveling together to Kentucky from North Carolina. As my grandmother would put it, 'They were as thick as thieves'.
My grandparents were first cousins, making me my own 3rd cousin. Of course, my siblings and first cousins on that side of the family are also my 3rd cousins.
Interesting.
I wonder how thier parents felt about them being married? I would never want my kids to marry my brother kids.
Doesn't that make you your own 1st cousin once removed ?
@@Lily2U1515 That would make SuperMagnet's parent who is the child of those grandparents, 1st cousin once removed to them. It would make SM 2st cousin twice removed to their such grandparent couple.
@@JudgeJulieLit Thank you for the reply, it does get confusing. I'm trying to work out this: one set of my great-grandparents were 1st cousins and then each had one set of their(the cousins) grandparents were 2 brothers from one family who married two sisters from another family. Lawd!
My 2x great grandparents were one of 3 couples that were brothers who married sisters. My great grandparents were the grandson and great granddaughter of the youngest and oldest sister in a family. Trying to decipher this in my tree online has been driving me crazy for years. I’m glad there’s a name and description for this. I also suspect my grandparents were possibly 3-4 cousins. Names, locations, dates all look suspicious.
Yes... I have a similar situation in my family.
Same with me but much further back, late1700's or early1800's. 3 sisters married three brothers.
I don't think that marrying fourth or fifth cousins is a bad thing.
As always, Diahan's presentation are so easy to understand. Love her graphics as always. Thank you for having her and on explaining for people what the difference is. It's a common misconception as to what endogamy is.
Glad you liked the video. Thanks for the comment.
This is one of the best things EVER that I have seen on these issues! Thanks!
I do love it that she talks about this as a range of complexity, because it is.
From a first-cousin marriage on one end to full Ashkenazi/Hawaiian on the other, my WV folks are somewhere in the middle. So many interconnections between lines across over 200 years.... Related to matches 3, 4, 5, 6 different ways.
I have found, though, that the effect dilutes in closer matches. The magnification matters more at 3rd or so and beyond.
For all the frustration, it is still fun figuring these bits out! And geographic outliers are GOLD!!!
Agreed!
This is a brilliant video. I had never placed any real importance on segment size. I have been putting too much importance on total cMs. Thank you Connie and Diahan for this video.
Great video with Diahan Southard. I have her book and find it very easy to read with great examples.
Glad you enjoyed it! Thanks again for your help.
That was a great video, fascinating and informative.
Glad it was helpful!
Thanks for your gen tv programs... i have been doing gen for 50 years and enjoy learning new tricks occasionally... I just retired in NY.
Thank you Loren!
This was super helpful - thanks!!
So glad!
Really excellent interview. Thank you.
Thank you Caroh
Superb explanations! I was not aware of the tiny vs. large segment importance of DNA sharing. For all the Americans who find endogenous ancestry... let me tell you, it keeps going back to the countries of origin, if everyone lived in tiny villages/farms! My roots are English & Iberian, and I have found, so far, 2 sets of common English ggg-grandparents, ties from my Iberian ancestors to all along the Canadian, USA Atlantic & Gulf Coasts (tying into Cajuns!), Mexico AND an English tie to my husband’s very long standing American family, which is based in N Carolina, Virginia, etc.! It is mind boggling!
This is brilliant. thank you.
Very very interesting. Kris
Thanks
It occurs to me that we think of these as "problems" because our idea of genealogy is too simple. This information helps me by expanding my awareness of this possibility. So instead of a problem, it becomes a possibility.
Humans practice many different ways of connecting. It's good to be reminded that the way we're used to isn't the only way.
Yes, she mentioned Acadian endogamy. My paternal grandparents came from New Brunswick where their ancestors lived for generations, so my paternal matches are one big match list. To make matters worse, lol, my husbands maternal And paternal grandparents descend from Acadians. Here in the US, my family did not know my husbands family, we just discovered all this in working on our trees and yes, took a DNA test, we match at the 5th cousin level. I’ll have to check out the segment sizes when I get home
Me too!
Oh boy! Good luck!
I live in Cape May County, NJ and am a descendant of the original county settlers of the county in the 1600s. For a long time the county was somewhat isolated. I read that at one time there were 72 households in CMC and 11 had the family name "Hand." When I began my family tree the "Hand" name crossed the tree at several points, meaning cousins had married cousins. My brother married a woman with the "Hand" last name, so I'm sure he probably married a distant cousin.
I'm not surprised. Small communities typically have the same family on several lines.
I am a poster child for Endogamy and Pedigree Collapse. Mom and Dad are 1st cousins 1x removed. Mom's father and dad's grandmother are siblings. Their common line came from France to eastern Canada about 1666, eventually they either went south into the US or headed westward into Quebec and Ontario. I have matches who are related up to 8 different ways and I've been able to trace those different ways to those matches and record those 8 different connections separately. What I'm finding is that dad's french surnames on his side have been anglicized on mom's side, an example would be St-Jean/St. John. My tree is more wreath-like than a typical tree and seem to go in a circular direction going back to people that are already in my tree.
Interesting. You must be an excellent genealogist to figure all that out.
@@GenealogyTV I'm about 22 years into it. In my little corner of the world, seems I'm related to everyone! The names begin to look very familiar. I start working on a match and realize I've already got a lot of their family in my tree! Did my DNA in 2016 and now I've got 15 other people who I've had tested. DNA research gets easier as you test more people of course. I was too young when my parents died to even have the foresight to test them, but have dad's sister and mom's brother who have tested (1C1R). I did not know when I started that mom and dad were so closely related and did not know that dad's grandmother and mom's father were siblings.
It’s amazing what we can figure out these days.
Studying the Royal Descendant Tree can be a great example of Edogomy
Interesting point.
@@GenealogyTV I only found this out due to my Royal lines.. I blame them for all the crazy lol just joking..
Thanks for the interesting video. I think I´ll sub your channel.
Thanks for the sub! I appreciate it.
Thank you Connie
Thanks
I have Cajun roots on my dads side. I think I am related to the entire state of Louisiana ;) Also on my mom's side my grandfather and his brother married sisters. So I see a lot of this.
Me too. We probably are cousins
@@ReneeHarris2018 I have tested on Ancestry and have a pretty big tree. Take a look :)
I'm a Guillory but I'm sure ours overlaps. My father was the first to marry outside of the community. My mother's family was direct lineage from the colonies and she was the first to marry outside of that. Her family was England, Massachusetts, Georgia, then Arkansas. His was France, Acadia and mobile, Evangeline, st Landry parish, Welsh and Jennings. My ancestry takes mine back too the same area for both
I am part Acadian from New Bunswick Canada. Cajun people originally come from the same area. We may be cousins.
@@lynnpayne9519 It seems likely. Do you have a public tree on Ancestry?
Very useful information. Thanks, Connie. It seems like some formula based on segment-length results might become a more reliable relationship indicator, doesn't it?
Two of my siblings and I have DNA results on Ancestry, FamilyTreeDNA and GedMatch. One would think (hope) the segment length results would be the same from company to company. For Ancestry and FamilyTree they are quite similar (on Ancestry my siblings longest segment with mine is 192, on FamilyTree it is 197 and 189). But GEDmatch is quite different. There it is 110 and 127, and my longest segment match with myself from two different kits is 146.4!
So all of this got me thinking... I'm wondering if that longest segment we have is from one line? If we take each of those pieces of DNA on the different chromosomes and ID which lines they came from, we might be able to tease out the pedigree collapse and ID who is who in the family. I've not tried it, but it might be a fun experiment.
Thanks for the information. Reviewing my DNA matchess and not finding and/or understanding the relationship or family connections led me to believe that some matches must be made by location. I also have several people who married and may be cousins but don't know how to prove it.
Glad it was helpful! "don't know how to prove it." That's where traditional genealogy comes in combination with DNA.
My husband's maternal grandfather was from Newfoundland. The family had been there since the mid-1700's and he has one pedigree collape at the 4xggp generation. Another 2 sets of 4xggp are from Jersey, Channel Islands, where they lived since the 1500's. I think almost everyone on his maternal side is related to his 2 or 3 ways....at least it feels like that sometimes.
Sounds familiar! My paternal grandmother was from Newfoundland. Her grandfather 's youngest brother had a very large family, & their kids & grandkids jntermarried over several generations. It caused some confusion when I was trying to figure out who my ancestor was, since I had so many matches to that gt uncle's line, & their cMs were so high! ( Btw: did you find a "JulieAnne" or two?)
I know which family you are referring to that went from The Channel Islands to Newfoundland, it’s spelt many different ways isn’t it. I started noticing it in many of my DNA match’s trees. A year later and I have now found over 70 matches in my DNA cousin lists that all relate to about 4 different names from Newfoundland. I am half English and half Australian and strangely my ancestors from both sides come from around Wiltshire, Somerset, Devon etc. I believe that many early Newfoundlanders emigrated from those counties in England, but we are talking about 300 years ago plus, so I guess the DNA from my ancestors in Devon, Somerset, Wiltshire etc must have just been passed to the Newfoundlanders and their endogenous community?? I can’t think otherwise why on earth I would have so many DNA matches from an Island where I know none of my ancestors actually lived. I must look into how large the segments are. Thanks for such a great subject. 😊
This is more common than I thought it might be.
Yes... I've found pedigree collapse in just about every tree/client I've worked with in some form or fashion.
My great grand parents on my fathers mothers side (North Carolina) were first cousins. People wonder why. It was rural. The family’s had lived in the area since before the revolutionary war & in Virginia before that etc etc
Yes... there are cousins marrying in almost every family though. Endogamy happens more often in landlocked areas or with groups that would only marry within their clan.
I started getting crazy results on Ancestry under the profile picture where you can tap to see how someone is related to you and I called them. I was told that when too many relatives marry and then their offspring marry each other, the program does what it can and it is not uncommon because people way back were born, married, and lived there whole lives in one place. They had to marry somebody.
Yes... exactly.
Excellent explanation!! Love this channel.
Much appreciated!
My Dad's great grandparents on his mom's side were first cousins. I was always told that was bad.
One pair of my great-grandparents were first cousins once removed. It seems to have caused generations of people with anxiety disorders, plus one suicide because of it. I suppose it depends on which bad genes are doubled up. All of my ancestors (so far) spoke German and went directly to Wisconsin, so I married a man whose parents were from Tennessee and Ohio. Turns out he's a match to me anyway!!!
Thank you for the video. I think my maternal Grandma's family was endogamous prior to immigration. Recent history is just collapse because people don't know they're related. The DNA amounts are normal, but the number of segments are noticeable more than any of the other lines.
Hello friend
Thank you! My paternal grandparents 3rd AND 4th cousins.
Interesting
Endogenous communities: Early Quakers of Pennsylvania 1683 to 1725, Berks County Germans between 1725 and 1765. Dutch of New Amsterdam and Puritans of Massachussetts circa 1620 to 1690. I have all of these issues trying to sort out who belongs to whom. So, not just geographic, but time oriented. Immigration and emigration helped to occasionally widen the branches.
Quakers have the best records. Follow the Quaker records. You'll likely have more success there. Here is a video about Quaker research. czcams.com/video/dPoUR-mSP7I/video.html
17:01 I didn't think I was endogamous either. Then I found out that nearly all of my paternal grandfather's paternal branches were in a small village of Switzerland with a population of like 800 from 1500 to 1800.😊
Thank you! A topic near and dear to my heart. I have Southern roots and my Great Grandmother married her First Cousin. I also have intermarriage between both sides of my maternal line. As if that was not confusing enough, there are also cross-overs to my paternal line from both sides of my maternal lines. That one's quite a mystery since they were widely separated geographically until the 1940's. As a result, I have matches on Ancestry who match both my maternal and paternal lines. It's quite a mess to untangle. Instead of a family tree, I call mine the family bramble thicket. ;-)
Too funny. Love it.
It stands to reason that endogamy would mainly affect the Kennel Club.
My husband and I discovered after we married that we were 5th cousins once removed. This was years ago through comparing ordinary family trees. It just happened we each had one family tree line and they met.
I doubt you'll see much of a difference in the DNA at 5C1R. Thanks for watching GTV!
Thank you.
You're welcome!
On a small island off of Messina, Sicily is a place called Lipari. My great grandmother was from there. I am related to certain families as much as 30 different times all leading to the same common ancestor. If you look at the church marriage records, there are dispensations for third-degree fourth degree and fifth-degree consanguinity for nearly everybody.
I live in the Amish community. 3 of my grandparents come from the Amish. I found out in the last year or 2 that my paternal grandparents are 1st cousin once removed. I also found out that my parents are 3rd cousins. THEN...I found out that my husband (raised Amish) is related to me like 3rd/4th cousins several different ways. My poor kids!! LOL
Yes... I can imagine the DNA must be confusing in your situation.
It's interesting that y'all mentioned the Timber algorithm for AncestryDNA. First of all, as you know below 90 cM, that's when filter weighted cM through most likely IBS as opposed to the cM shared through IBD.
Even that, I find that it matters more on lower cM like around below say, 40 cM where segment amount is the determiner of my relationship with a match is. At least IMC. For example, I have a match that is 74 cM but the unweighted, unfiltered largest segment match is 82 cM(only one segment) and we even have the same surname with shared matches with that clan, even with my biological paternal aunt. We also share the same additional community; Early Virginia African Americans too.
So in your opinion, how low a cM match has to be for matches like this matter wrt what is IBD and IBS? Because I have matches well over 90 cM with largest segment matches are in the 20s and 30s.
For general genealogy I mostly use cM above 20 and rarely go as low as 10cM. As for determining pedigree collapse you want to look for segments longer than 20 cM which indicates there is no pedigree collapse. If you have a lots of smaller pieces under 20cM but still add up to 90cM, that is an indication there is pedigree collapse or endogamy within your ancestors. Personally, I would not worry about this too much. Focus on the traditional research.
PS Happy New Year!
PS... Back at cha! Happy New Year!
@@GenealogyTV Thanks!
My father is 3rd cousin with my mother and also he's 3rd cousin to his mother in law. Also my paternal grandmother is 2C1R to her husband my grandfather. I have tested my mother and my paternal grandmother and I can confirm they are 2C1R.
My parents are like 4th cousins, their families intermarried in Germany in the 1850s. So my maternal Great Grandmother is my paternal 3rd great aunt. My maternal 2nd Great grandfather is my 3rd great Uncle by marriage. My maternal and paternal grandmothers families intermarried, so they had common cousins. My paternal grandmother and maternal grandfather were 3rd cousins. All of these families came from the same areas in Bavaria and Prussia and they migrated to the U.S. in the mid 19th century.
Sounds like you have a good understanding of where you family lines came from. You are a lucky guy Rick.
Check out the pedigree collapse in Quebec, Canada families. I can trace many of my Geneology lines to the same core families 4 to 5 generations in the past...
Yes, I think pedigree collapse is in just about every family at some point.
My grandmother has a match at 198cM who believes they are 1c 1r, awesome until I look at my grandmothers clustering and she only has two clusters from 400 cM to 50 cM. Sometimes I think people need to take a step back and take a deep breath. I have names of my grandmothers grandparents but have been unable to prove that is their real names or where they link to beyond my grandmothers mother.
Wonderful video, thank you very much.
That's so nice of you Marissa Rosa,,,,,,, am so glad to hear that I have a lovely grandma 💝 hello 👋 how are you doing I hope you are having a wonderful day.
Richard Carpenter of the pop group the carpenters married and had children with his adopted first cousin. If they have no blood relationship, there is nothing really bad about it
I also have multiple relationships. Mine I have concluded is NOT cousins it is my 2nd great aunts or Uncles/ 2nd cousins on my paternal side marrying 2nd great aunts and uncles/2nd cousins on my material side... it jumps the DNA centamorgans up dramatically. When they should be 100 or so, its more like 200-300 making it look like a closer match in the tree.
My family on both sides have resided in this same town since 1860's and before that some of them on both sides came out of same counties/towns in WV and KY. Its fascinating. Both sides were here in America long before revolution War. Before that it was northern England and Southern Scotland. It is extremely hard to explain any of this to people who I create trees for when this sort of stuff happens in their lines...
I saw on a forum that it has been determined that marrying your cousin is "ok". Just because something goes from 2-3% to 4-6% doesn't mean it is insignificant. It means it doubles your risk of deformities etc and that probably doesn't take into account things like ADHD, OCD, Dislexia, Bipolar etc. -at least from the studies I have read. I suspect the severe mental illness in my tree is from decades if not centuries of first cousin marriages and the recessive issues that hide in those generations. Can Diahan speak on whether it is worth it to try and find a 4th great grandmother from DNA cousin matches? Great idea for a show that has never been done. I feel so badly for the forgotten matriarchs!
Thanks for the compliments. I don't know if I can get Diahan to respond. She is a busy lady. It took a while to get her on the show.
My father has pedigree collapse but my mother has endogamy due to a 400 year period in the same village with multiple crossovers between a few families. To make things even more awkward there are signs that they have one or more common family groups or ancestors.
And then looking at my matches... I have several matches on the endogamous family where I have 4 generational connections amongst my matches which help identify which recent ancestor provided a block of dna but there are several that are likely from one of the early ancestors.
I then have a handful of matches with 1 segment over 30cM and we have no apparent connection in 6 generations. 2 I have been concentrating on with 1 possibly being connected to an unknown father line. But the other one is looking like a combination of ancestors but only one segment has passed down but maybe a collection of segments from multiple cousin lines, So, rather than being 4th cousin we could be 10th cousins several times over with segments that merge into a single segment.
Yes... it looks like you are gaining a good understanding of this. I'd still group my matches though, it may help you figure out the complexities of your genetic tree.
@@GenealogyTV oh yes I do. And it clearly shows several interconnecting matches. Matches shared between my maternal grandparents, my parents themselves and some of my fathers maternal line connections. Having London, Essex and Wiltshire shared amongst most of my grandparent line connections. One of my 1 segment 30cM matches appears to have connections with both my parents. And we both appear to have connections to another family that we can’t find his connection to but I think I found mine. With both of us having several generations of ancestry and seeing no common names - apart from Smith rofl - it’s annoying the hell out of us but we persevere.
I try to sort my parents DNA matches into 8 groups for each, one for each of their great-grandparents. It works pretty well, but there are a couple cases here and there where distant matches seem to be fit into more groups than they should.
... and thus you might be seeing evidence of pedigree collapse. Here's what I did... and figured it out rather quickly. I added my tree to WikiTree. They have a fan chart that when you colorize it right, it shows duplicated people in the fan chart. I didn't realize that one couple of my great grandparents where actually second cousins when they married. It was colorizing the fan chart that helped me to see it.
My paternal grandfather was one of two brothers that married two sisters, I ended up with a bunch of double second cousins, many of whom I can see on Ancestry DNA. My mother also had cousins on ancestry, some good known relationships with reasonably strong cM numbers with me.
Shared matches is where it gets odd - a few of my mothers relatives have high cM numbers with me, but they show with “shared matches” with my paternal double cousins as well. Ancestry reports just my cM values as high with the entire list of shared matches - it looks strange because I’m sure the shared match values with the target relatives are actually quite low ... or maybe they aren’t and I am missing a shared relative within 4 or 5 generations or so? Sure wish I could see the cM values between two of my matches!
I’m going to research that cM summing formula now that I know about it.
Just remember that having your maternal cousin A also match your paternal cousin B does not mean that you all three have common ancestors. I have many cousins who are related to others of my cousins through their "other" parents -- the ones not related to me. Just about everyone does, but most won't realize how they relate to each other unless they (like me) have been researching family for a long time and have a full, accurate tree.
@@karlayork877 Good point. I have about 4 or 5 close DNA relatives that cross over. It just looks strange when I see these high cM counts listed on Ancestry from both sides in “common matches”. I would just like to see what the cM value is between B and C, And B and D, and B and E, etc. Ancestry has to have that in the database because they show it to B and C.
Some of my paternal and maternal family came from the same county in Ireland, and my maternal grandmother used to say there were some Clancy cousins in the family somewhere. I suspect there actually is a link, but I don’t know if I’ll ever find it.
@@ProgRockKeys I totally agree about needing to see how B & C, B & D, etc., match each other. A relative few of my overlapping matches did come from the same places as each other, but most of them are more along the lines of my maternal grandmother's great aunt went to California with her husband and children, while my paternal grandfather's grandmother's brother went to Oregon, and then some of the California descendants happened to go to Washington and so did some of the Oregon descendants, and they happened to meet and marry, giving me cousins who match both sides, even though my grandparents were not at all related to each other.
I have found i have to develop both sides of cousin family trees because sometimes i coukd be related on both sides of their family.
I have the same root ancestor couple 2 times over on both of my maternal grandparents side. I am my own 4th and 9th cousin. My maternal grandmothers last name was the same before she married as after. They are French Canadian.
I see this a lot. Sometimes I wonder if they even knew they were cousins when they married.
Mine knew very well. They did have what was called " country wives" who were native women fur trappers hooked up with. Often a founding would be placed on real wife's door stoop so that is why I don't have 3 eyes and a tail. If I told you the family name you would be very familiar with them.
I have three endogamous groups that make up the bulk of my ancestry from the last 500 years: Mexican, French-Canadian, and a rural community in the Florida Panhandle.
As you probably know, the records are great for French-Canada, and of course the endogamy is crazy high.
The rural Florida Panhandle, the records aren’t that good due to burned counties, but I know that some people knew the relationships and others had no idea how they were related to the community.
As for the Mexican, that’s what I love. It has the same detailed Catholic Church records as French-Canada, only they went a step further and when a couple went to the priest and asked for permission to marry, they had to bring witnesses (usually 3) who would vouch for their identities, and they would undergo what was called an Información Matrimonial or what we call a Marriage Investigation in the local genealogy groups. Those are sheer goldmines. They would talk to the priest and give their place of birth and undergo an interview where the priest would determine if they needed special permission to marry based on blood relationships or marital relationships, and even castas or the race of the parties. If it required further investigation, or if there was any question about how the couple were related, the priest interviewed others and went through parish records to determine it and would list out the couples’ parents, grandparents, great-grandparents, etc until they reached the common ancestor/ancestral couple. In really great cases, the priest or scribe got creative and literally drew out a family tree in the Marriage Investigation registry books. Man, those are a treasure trove and I love finding the Marriage Investigation for ancestors. Of course, if there was no inclination that they were related, then all you get are two or three pages of interviews and witness testimony, but even that is enjoyable. I never understood why the Catholic Church was doing this in Mexico and not doing it at the same time in French-Canada. It’d be so amazing to have that to help untangle some relationships in that area. I’m just happy when I find a fille du roi that I didn’t know about.
Endogamy can be a pain for DNA, but sometimes, in some locations, it’s been helpful in the paper trail.
My auto cluster at my heritage basically times out as first 100+ matches creates only 1 large cluster!!! Crazy
So cool when Diahan mentions Acadians, that’s me, lol.
Interesting
Connie...did this episode give you another way to confirm our Joel Davis Jr. find? thanks, Bradley Martin
that is "your" Joel Davis Jr." not OUR...sorry
Yeah, no. I had already looked for pedigree collapse on the Davis line long before shooting this episode... But you’re on target with your thinking. That would’ve made the DNA look higher in those close cousins, if there had been pedigree collapse. I have ruled out that possibility as well.
Greek village issues. Sharing a lot of dna but the segments are short. It's maddening.
Dr Southard, if you are looking for cousin-cousin marriages, there are plenty in Bradford, Yorkshire, England.
:)
My German side of the family had it all perfectly.. laid out.. and MY HERITAGE messed it up.. my Italian side is a HUGE MESS because of the "CENSUS" which everyone lied on.. now 23 and me.. just integrated w/ My Heritage and it is totally messed up.. lucky for me,,, I actually had the hard copies and both sides of my family and my husbands actually have hard copies and his grandmother (English) did a book which is in the DAR.. so I KNOW WHICH ones are correct. GOOD RECOMMENDATIONS. My father met my mother in WW2 Germany to AVOID MARRYING ANY COUSINS... thank God.
Would Gedmatch tools not help with this situation too ?
I just found a cousin, who parents shared the same last name and the same ancestors. He descends from one ancestral couple 20 times between 4th and 6th great grandparents. They are also my ancestors. They match my older cousin at 224cM across 12 segments, the largest being 43cM. But they should be 4th cousins, once removed based on our shared ancestor.
Connie,
How do you switch yourself in your tree as you mention?
I'm trying to remember exactly what you are talking about. I think it had to do with changing yourself as the home person in the family tree on Ancestry. If you are wanting to do that, it is your Tree Settings. To do that go to Trees, drop down to Create and Manage Trees, then to the right of your tree you want to change, there is a link called Tree Settings, then in the right side there is a home person. Click the Change link to change it to someone else in your tree.
My maternal grandparents were cousins
Love the video! Especially "multiple relationships" - & Connie 's concept of "reverse engineering ".
Seems to me that 's my clue to figuring out who my maternal 2nd gt grfather actually was.
(0 DNA matches to the name he used from marriage to death.)
However, I've a mass of "shadowy" (appropriately remote) matches to 4 well-known family names living in his area - who intermarried to a dizzying degree for 150 yrs from their arrival c1760. (They also mixed somewhat with 3 of my other local lines- enough to muddy the waters - though maybe far enough back to be irrelevant? )
Deciphering the cMs after layers of 1st cousin marriages leaves me flummoxed - or are they merely pointing the way?
It can be difficult to tease out the DNA relationships when you have pedigree collapse. This is when I go back to traditional research until I can figure it out.
@@GenealogyTV Thanks Connie! I have the impression that - providing I'm actually related to the person(s) whose DNA is repeated in that collapse - the DNA I share with that match suggests a relationship a "degree " closer than it actually is - ex: a 4th cousin may look like a 3rd. (The higher numbers do get my attention..!)
Those four families also intermarried a bit with my other - known- NS families, but only occasionally- red herring. For now I'm stuck with digging through matches - I suspect a realistic goal might be to identify JR's grandparents. I suspect their best was done to misdirect attention from his birth identity. (So- I look at who was where, birth years, etc.)
When the travel ban is lifted, I may get to archives. Thanks again!
Yep. Good luck.
@@GenealogyTV Thanks! I'll need it!
I have a suspicion that 2 of my great great grandmother's are sisters or cousins. They both have the same surname and always lived within a house or two of each other. One of their children married the child of the other. Their grandchildren (my paternal grandparents) were neighbors when they were 12 which got me thinking about the whole thing. The other possibility is that they are not related at all but were enslaved by the same Wilson family and both took the same surname and jist remained close. I'd like to eventually figure this out.
I heard the phrase "brothers marrying sisters" more than once here, perhaps with less concern subsequent times.
my surname grandfather (b1862 S GA) was one of four brothers who married four girls from another family, two girls were sisters and the other two, also sisters, were their half nieces. Now I've always assumed that would increase cMs in subsequent generation relationships (also producing what I call double cousins), but that would not present the same complexities described here, would it?
Now in the girls family, 5 and 4 generations farther back, there was a marriage between 1st cousins b 1763 and 1773. Is that far enough removed to be inconsequential in genealogy?
there were slim pickings in south GA back then and many of the families had emmigrated from the same areas in NC but one of these 1st cousins families came thru VA via SC.
my most pressing brick wall is my surname gg gpa, seemingly totally undocumented, and my g gpa was estranged from his mother.
You might consider taking Diahan's DNA courses. Here's my affiliate link if you're interested. www.yourdnaguide.com/ref/6/
Double first cousins!
Ahhh, large cM's with short strands...I never knew what to think of that.
Yes, we learn something new every day!
The segment size for half relatives can be lower than 20 cM and be a legitimate (not endogamous) relative.
Thanks for the feedback.
Very informative video, thank you!
My 4th Gr-Grandmother married her 1st Cousin and had 2 children, one being my 3rd Gr-Grandmother, w/him. However officially he is not listed as their Father, and she later remarried as did he. And wherever she moved, he was never far away! It would interesting, and creepy, to hear more details if that were possible.
Interesting. It's amazing how often I hear stories like yours.
@@GenealogyTV Thank you for the reply!
My dad and his first wife were first cousins, the children from that marriage my half-siblings are also my second cousins. I'll be interested to see how much they match me by DNA, just need to see if one of them will test :)
Yes. If Diahan’s comment is correct, you should be able to figure out about how many CM came fro each of the two relationships.
Don't think 1st cousins should ever marry. Imagine the relationship don't work out then your with your grandmother trash talking your ex. Grandmother says don't forget your ex is my child to so I won't tolerate you trash talking them. You then go damn I forgot.
Would most of those less than 10cm matches in Gedmatch ancestor groups/Facebook groups just be IBS then? Not IBD? I'm thinking of groups like ones for ppl with Colonial New York or Colonial New England roots.
It's hard to say. There is no hard and fast rule to separate out IBS from IBD. Personally, I don't mess with low cM counts. But then again, I have plenty of DNA cousins to explore.
Redbone Louisianan here are they doing that for us
What does it mean when you only share one segment, and the size of the segment is larger than the shared cM? I share 1 segment, 38cM but total cM shared is only 35cM. I am assuming that 38cM means no endogomy or pedigree collapse is that correct? Great video, thank you Connie and Diahan.
That’s odd that your longest and only segment is slightly higher than the total. Yes that likely means that there is no pedigree collapse on the line you share with that match.
Thank you so much.
@GTV: I've the same situation several times in the 4C range. I've 4 ( previously unknown to me) families that intermarried for 150 years. Am I seeing a micro-endogamy? (My search for a 2nd gt grfather is leaving me cross-eyed & dizzy!) Need I say, also lots of cousin marriages?
That sounds like the work of Timber, the algorithm. If you go to the match’s page, it’ll now show you the weighted and unweighted shared centimorgan amount. Timber tries to be conservative with the DNA matches, so the default is the weighted amount. Once you’ve clicked on the match, under where it states the predicted relationship, there will be a line that states the percentage of shared DNA (directly above the Message button). Click on the blue part where it states how much shared DNA there is and it’ll take you to another page and there it lists the unweighted centimorgans shared and the longest segment. Sometimes there’s a big difference between the weighted and unweighted amount and I suspect that is what is happening here.
My grandmother married her first cousin. I have tried to prove they were not first cousins but I have failed.
I have one my mother's side one individual who is my3GGF through 1 marriage & 4GGF through another. He had in total 20 kids by 2 wives! Also in the line I have a 5GGF & 6GGF, the 6th being through 2 lines. I don't have this as much on my dad's side but his aunts married brothers so that would be something to contend with as far as cousins. On his line way back the intermarriages were more in the New England area. It's why I always laugh when people make their little disgusting jokes about the family trees of Southern people being a stick. Umm, it happened up north too. The wagon only went so far and people would know their cousins came from "good stock".
I feel like I need to go back to school to apply this DNA stuff to my research, lol. I need a "DNA For Dummies" 😮
"Endogamy" looks like "End of Gamey" like when you breed a Jackass and a horse! I must watch this video ! Sometime it seems as if DNA has created as much confusion as it clears up. I wonder what it would do with my father's family and the double cousins!
Ha! Funny.
Question for the experts: If you know you come from a highly endogamous population (I'm French-Canadian on both sides of my family for generations), is there any point of doing DNA tests in the hope of finding info? Especially given that French-Canadian sources are well-documented and easily accessed through a genealogy service? I love seeing videos of people saying this much European and this much Asian, etc, but I feel like it would come back 100% European and there would be no new info in there.
Well, yes. You can find living cousins, and their trees. Ignore the DNA and match up trees. It's fun. The DNA is then just a pointer and does not tell you the specific relationship.
@ I ended up doing the test and I was right, almost 80% French with a bit of German (which I knew from family history), some English and some Scottish. And not a single person which is more than a 3rd cousin. It was still worth it though as it confirmed that my lactose intolerance was not all in my head! hahahahah
Does Endogamy offer proof of association? That is I have a historical figure in my ancestry 12 generations back. She is native and there are no records to be found. I know that my R1b maternal ancestor that she is married (Assumed again no records but was recognized as his widow in documents) The community was New London Ct. and I have a circle of family names that do not branch out a lot for 200 years. The same surnames appearing and reappearing from there into Nova Scotia (King County) for another 100 years. Can I share the Endogamy of the current Mohegan Tribe (Although they appear to be largely African American in appearance today). I am looking for a needle in the haystack I know at 12 generations but our cousin (Yes James Fenimore Cooper was hiding his mixed ancestry from UNCAS 2 centuries earlier) almost made the Mohegans (Mohicans get mixed up in history) extinct in the Minds of Americans. No we didn't we were my Cousins Ethan Allen and Remember Baker in the Green Mountain Boys and Buffalo Bill Comstock. Always on the edge of Indian culture.
Thank you for posting this I will contact my American Cousins (I'm in Canada) and see if we can concentrate on Tiny bits of DNA and find a common source. Its not just important to me, your American President FDR is from this family tree as well as Prime Minister Sir Robert Borden. It sort of puts a new light on matters when the descendants of a former slave can rise from chains to be US president and a Prime Minister. Can you recommend the BEST DNA test kit for this project.
I would always suggest starting with AncestryDNA because they have the largest database of test out there. You'll have more cousin matches with Ancestry. You can then download the DNA results and upload them in many other places, if you feel the need. Here is my affiliate link should you choose to use it, I'd appreciate it. prf.hn/click/camref:1101l4aFW/creativeref:1011l36543
How do you enter these relationships into a family tree program?
What family tree program are you using?
@@GenealogyTV I havent found one I like yet. Do you have any suggestions where I can enter information sources and notes for each person?
I have one match at 112cM (recently deceased) who I have 3 relationships with: 1C2R is the closest. This one is through my paternal grandpa's mother. The match's mother and my great-grandmother were sisters. Also, 4C1R (through paternal line 2nd great-grandpa's father) and 3C2R (through paternal line 2nd great-grandpa's mother). This is the only match that I have been able to determine multiple relationships with so far and none of the ancestors are re-used for either of us or (at least they don't appear to be). So, it would just be multiple relationships, not endogamy or pedigree collapse, right?
Have you grouped your DNA matches on Ancestry? If not... Here is a playlist I recommend you watch in order to understand how to group your DNA cousin matches on Ancestry into branches of the family tree.
czcams.com/play/PLiMXWjHlj5RSR-KaPX0jLYC-zFxpqU6OJ.html
@@GenealogyTV My initial response seems to have disappeared. Yes, I have charted them in Google Sheets and sorted them on Ancestry, too.
I found another multiple relationship match along two of the lines mentioned above, too. She matches me through her father through my paternal grandfather's mother and through her mother via my paternal grandfather's father. The man mentioned above shows up in 3 lines of my Leeds chart. This other match is only in one column, the one with her father as the column head.
Thank you for the link. I will watch the videos soon.
Connie I am seriously confused. Talking about cousin marriage that would mean like for the Ancestry DNA test only the mothers DNA would come up because the mother and father are cousins?
I don't understand the counting.
I am glad and Thankful you shared.
I have this on 23andme, where my mother was tested but Daddy had already been deceased and was not tested. For everyone, like myself and my siblings, we would match on both sides. However, they only list my mother when the match is to both parents. Fortunately, I know my siblings and their kids.
It does take some study to get the concept.
@@GenealogyTV Is there an easy way to determine which brother in a big family sired a daughter and which brother sired a son...with two sisters? This was so long ago, 1928! We are pretty sure we know but a relative started and passed on a hateful rumor that the same brother impregnated both sisters. Both sisters married other men later, and both sisters kept pictures of their own specific "brother" for the rest of their lives. I almost think just looking at the photos and knowing the babies after they were grown, I can tell which kid belonged to which brother.
That’s rather complicated. You would need to get the DNA from all the descendants to see and compare. This would take a detailed look. I can’t really answer that in a comment.
I think that u should mention that the catholic church and the priest in every town village worked hard to stop cousins marrying and also they used info that was told in confession to keep say brothers and sisters or first cousins from marrying and u can see this in the incredible beauty of the people in italy and all over europe. this is very very different from say mid east syria etc where first cousin tribal marriages were encouraged and tons of gene diseases crept into the populations. in one case the family extended family of 80 individuals or more last the ability to stand on two feet they literally crawled on all fours because of a loss of a balance gene bc of genetic damage from first cousin marriage
Wow. Sad.
That's true about Catholic priests/bishops trying to stop inbreeding. In Western Newfoundland, the local bishop in the '50's encouraged families from the eastern side of the Island to move to an area where he was very concerned about the closeness of the relations. Western NL is part of the Acadian/Maritime group.
Double cousins, Two Snook Brothers GGrandfateher and his brother married twos sisters
I'm sure that is a challenge from a DNA standpoint.
is the reason why someone of us have our father mitochondria related to pedigree collapse ? also do you know the role in the rise of cd8 cells due to this ?
If you have the same mitochondrial group as your father, it's probably just a coincidence. There aren't that many groups. I'm an *H* which is the most common in all of Europe.
@@rridderbusch518 well i found out my parents had common ancestors in Europe in particular Ireland , so i dont think its a coincidence
My grandmother has a match with 630cm across 24 segments longest segment being 82cm. What do u think should I reach out to the match?
I would. The probabilities are... 62% Great-Great-Aunt / Uncle Half Great-Aunt / Uncle Half 1C 1C1R Half Great-Niece / Nephew Great-Great-Niece / Nephew
What does your phrase " once removed" mean?
It is a generational difference. Say your first cousin has a child. That child is your first cousin once removed (1C1R). If that 1C1R has a child that is your 1C2R (first cousin twice removed).
Even if cousins of mine (without endogomy) have 34 cM I'm finding that we are within 5 generations! That's still pretty close to find an in common ancestor...
I found out I have some cousin matches that match both sides of my family. My parents don't show up as each other matches but they seem to had distant cousins that married each other. By the way how much CM would half siblings/ cousins share. Say a woman had a kid with two brothers or a man had a kid with two sisters. Unlike normal half siblings or 1st cousins that only share 2 grandparents they would share 4 so could a half sibling who's also a 1st cousin share as much DNA as full siblings?
Go to DNAPainter.com and look for the two different relationships (range of cM) and then add the two together. Since you are adding one range plus another range, you end up with a range. For example (300 cM to 600 cM) plus (200 cM to 400cM) equals (500 cM to 1000 cM).
This type of relationship is called a 3/4 (three quarters) sibling. It’s actually not at all unusual if you go back in the range of 125+ years, and in fact, it was often encouraged.
In many situations that our ancestors found themselves in, death rates were high and without societal safety net programs, people often remarried quickly out of necessity. Whether it be a widow needing a new husband so that she wouldn’t have to send her kids to orphanages or a widower that needed a new wife to take care of his young children while he worked, and sometimes it was both and you’d see two newly widowed people quickly remarry each other.
In many places, it was encouraged and even expected that, for example, if a man died, that his unmarried brother (if he had any) would step in and marry his wife and take care of the children out of family responsibility. The new couple often had children together, so the children would be both half-siblings and cousins with the children of the new union, but we now refer to this as 3/4 siblings.
My daughter's half sister "same dads different moms." Had a child with my brother . So her niece is also her cousin. What would that look like in DNA test. Would that make her niece/cousin look more like a sister?
Most likely, yes. You can go to dnapainter.com/tools/sharedcmv4 and look for the expected range of both relationships and add them together. So the average for a niece is 1740 + the average for a 1C is 866 = 2606 which is in range for a sibling at an average of 2613 (range is 1613-3488).
So the range on siblings is that full and/or half ? Also thank you for getting back with me . I love DNA stories. I don't love the ones like this . My brother is a pig.😔
What would be the normal amount of shared DNA segments, for borthers, sisters, half siblings and etc.
Look up the 'Shared cM tool' on the DNAPainter website.It has all the answers for that.
Yeah... what Caroh said. :) Thanks Caroh
I cannot trace the origin of a 30 centimorgan segment on my Sephardic side shared with Moroccans and Mexicans ouch. Only thing I can say it’s Sephardic in origin and the Mexicans only share 6 to 8 centimorgans of it. Only cousins I’ve proved are ones I know out to third who I know their families. My royal lines go back 700 years no matches that far back. Population segments just mean they are 700 or so years ago. Common ancestor just beyond the genealogy tree
Yeah... Autosomal DNA can only go back so far before it gets so small that there is no trace or viability.
I've seen some vids of Mexican jews that had been there for generations. Also they say a lot of people migrated from Europe before and after the wars 1&2 to South America.
I can only identify 3 out of 4 lines. My father was adopted. We have his fathers name. We don't have his mothers name and cannot identify her line. DNA detectives have tried and they have no clue either. There don't seem to be people that have higher cM's than any one else. I am only guessing that she was related in some way to his side of the family. Did try my Grandfathers sister in law's name's and all but one name came up clean. The Williamson name however didn't. What this say's is that I have ancestors on that line that go back farther than they should. All the other sister in law's I am only related to their children.
That is odd. I hope you can figure it out someday. Some times you have to wait for more DNA results to come in from newer test takers.
@@GenealogyTV Newer test takers? I have had mine done for over two years. And from what I can look up, my Father had only one cousin who didn't get her DNA tested before she passed. And if his mother was an only child of an only child, there isn't much chance. I would have to have a DNA cM counter that was exceptional and very knowledgeable about what trees there are. I have checked a ton of them and only a few go back far enough to get anything from then. And then when you search these people on the trees out, they don't have enough info.
How do I un-join
Hi Susan. Sorry to see you go. For the CZcams channel, here are the instructions to cancel your membership.
1.Go to CZcams.com
2. Sign in if needed.
3. Click on your icon in the upper right corner.
4. Click on Purchases and Memberships
5. Click Manage Membership on the membership you wish to cancel.
6. Choose to cancel.
Maybe I'm missing something, but why would you want to discard relationships from distant endogamous ancestors just because they're distant? Personally, I would still consider those relationships important and interesting to note - even if not much more than a note can ever be made of them. That part sounds more like a value judgement, or am I missing something? (Granted, I just learned this word today.)
If you have closer matches from the same line then it is a lot less work to research the closer lines than distant lines. For example, a 2nd cousin likely has great grandparents in common. A 6th cousin likely has approximately a 5X great grandparents in common. To research all the descendants from your great grandparents is much less than researching the thousands of descendants from 5X great grandparents. However, if that distant DNA cousin is all you have then go for it. Keep in mind distant cousins also could be a false positive match if the cM's are less than 8-10 cM's.
Is it possible for a female to discern the genealogy story of her father's mother's mother?
That depends on a lot of factors. Autosomal DNA would be most helpful here. All services offer Autosomal DNA... like at Ancestry.