Pictured below is Marie, a three-month-old kitten who was recently adopted from the Berkeley Animal Shelter. Marie received very little attention from people during the first several weeks of her life, so she’s still a bit shy. Once she feels comfortable, though, Marie becomes very active and is enticed by the treats, toys, and attention people have to offer her.
What makes Marie especially unique, however, is that she is a female orange tabby. The vast majority of orange cats are male; this phenomenon has a genetic basis. Every cat has two sex chromosomes, with females having two X chromosomes and males having one X and one Y chromosome. The gene for orange coat color is located on the X chromosome (meaning it is sex-linked) and is recessive, meaning that the presence of the dominant allele on another X chromosome essentially masks the orange coat gene. Thus, for a female to be orange, she needs to have the recessive allele present on both of her X chromosomes, which is statistically quite rare. Male orange cats are much more common because they need the allele to appear just once, on their only X chromosome.