The genetics behind cat fur color and patterns are fascinating. Orange fur (B) is dominant over black fur (b), and piebald, which refers to white spotting (S), is dominant over non-white spotted (s). Both of these genes are located on the X chromosome.
In cats, somatic cells contain two X chromosomes in females (XX) and one X and one Y chromosome in males (XY). This means that the expression of these traits can vary between male and female cats due to the presence of one or two X chromosomes.
For example, a male cat with the genotype XBY will have orange fur, while a female cat with the genotype XBXb will also have orange fur because the orange allele is dominant. However, a female cat with the genotype XbXb will have black fur.
Similarly, for the piebald trait, a male cat with the genotype XSY will have white spotting, while a female cat with the genotype XSXs will also have white spotting due to the dominance of the S allele. A female cat with the genotype XsXs will not have white spotting.
These genetic principles explain the variety of fur colors and patterns seen in cats, making each one unique.