Mules and Horses - And Example of Selective Breeding and Producing a Hybrid Animal

Teachers, do you teach about selective breeding? www.teacherspayteachers.com/S... Mules are a hybrid of two species of ungulates-a female horse... Mules are a hybrid of two species of ungulates-a female horse and a male donkey. They end up with an odd number of chromosomes which causes issues when egg or sperm cells are produced. Thus all mules are sterile and cannot reproduce themselves.
The type of post-zygotic barrier that maintains reproductive isolation between the horse and donkey, leading to the sterility of their offspring (the mule), is called hybrid sterility.
Postzygotic barriers like hybrid sterility occur after a zygote has formed. A zygote is the first cell in the development of an organism that reproduces sexually. These postzygotic barriers, such as hybrid inviability and sterility, prevent successful reproduction even when fertilization occurs.
Specifically, hybrid sterility is a form of postzygotic barrier where reproduction leads to the birth and growth of a sterile hybrid, meaning it is biologically unable to reproduce offspring of its own. The mule, a hybrid offspring of a male horse and a female donkey, is sterile and thus maintains reproductive isolation between horses and donkeys.