This article was written by Laurence D. Hurst from the University of Bath . It was originally published by The Conversation. You may not be aware of it, but one of your chromosomes - the X chromosome - is considerably different from the rest, and.
When using autosomal DNA, the X chromosome is a powerful tool with special inheritance properties. Many people think that mitochondrial DNA is the same as the X chromosome.
Calico cats are almost always female because the X chromosome determines the color of the cat, and female cats—much like all female mammals—have two X chromosomes, whereas male mammals, including common male cats, have one X and one Y chromosome. Since the Y chromosome does not have any color genes, there is no chance he could have both orange and non-orange together. One main exception to this is when, in rare cases, a male has XXY chromosomes.