For female felines, the process works a little differently because cells cannot receive instructions from two different X chromosomes. Lyonization: The Inactivation of X ChromosomesĮach cell of a biological male cat receives instructions from two chromosomes, one X and one Y. In 2018, a rare male calico cat was barred from competing in cat shows.) Strange, right? Not if you know how those distinctive orange, black, and white splotches are produced. A typical male cat with one of each sex chromosome (XY) cannot have a calico fur pattern, which means that almost all calico cats are female. Cats receive an X chromosome from their mother and either an X or Y chromosome from their father. Sex chromosomes work the same way in cats. This is why all humans have an X chromosome, but only some have a Y chromosome. The Y chromosome, on the other hand, doesn’t carry many genes, and none of its genes are necessary for the cell to survive. The X chromosome is large and carries hundreds of genes, some of which are essential for survival. Biologically male humans (XY) receive an X chromosome from their mother and a Y chromosome from their father.Biologically female humans (XX) receive one X chromosome from their mother and one X chromosome from their father.Most humans get one sex chromosome from each parent: Understanding the Genetics of Calico Cats A Brief Overview of Sex Chromosomes More specifically, you can learn about epigenetics, or the study of changes in organisms due to the modification of gene expression, not the alteration of DNA. Known for their distinctive patches of black, orange, and white fur, calico cats illustrate a genetic process known as “lyonization.” Whether you adore cats or you’re allergic to them, you might be surprised to learn that you can better understand genetics by studying calico cats.