X chromosome

Using skin samples collected from variously colored cats, the researchers homed in on a mutation on the X chromosome that increases the amount of a protein called Arhgap36 only in pigment-producing cells called melanocytes.

Multicolored cats from such a cross are almost always female, suggesting the gene variant that makes fur orange or black is located on the X chromosome.

It may have some genetic material missing, damaged or swapped with the X chromosome, depending on the variation.

The team identified over 140 new genetic risk loci, increasing the number known eight-fold to 164, including three on the X chromosome.

The team found that, compared to the X chromosome, the Y chromosome varies greatly across ape species and harbors many species-specific sequences.