Researchers link orange cat coloration to DNA mutation — ScienceAlert
Two independent groups of researchers have linked orange cat fur coloration to the absence of a DNA fragment in a non-coding region of the genome next to the ARHGAP36 gene. As ScienceAlert reports, this deletion likely explains the unusual inheritance pattern of orange coloration and its different expression in males and females.
A team led by Stanford University geneticist Greg Barsh found that skin cells from which orange fur grows produce 13 times more RNA from the ARHGAP36 gene than skin cells of cats without orange hair. The scientists identified a 5-kilobase deletion in the DNA sequence before the gene, which likely affects its activity.
The deletion was found in all orange cats examined by the researchers in a database of 188 animals. It included 145 orange cats, six calico or tortoiseshell cats, and 37 non-orange cats.
Why males are more often orange
The mutation is located on the X chromosome. Males have one X chromosome, so if they carry this mutation, their coloration is predominantly orange. Females have two X chromosomes, one of which is randomly inactivated in each cell. As a result, the X chromosome with the mutation may be active in some areas of the skin, while the one without it may be active in others.
More current news is available on the UA.News Telegram channel Telegram.
This mechanism explains the patchy combination of orange and black fur in tortoiseshell or calico cats. In rare cases, females inherit the mutation on both X chromosomes and may be completely orange.
How the pigment changes
A second group led by Kyushu University geneticist Hidehiro Toh also linked ARHGAP36 to orange fur. According to its findings, increased activity of this gene suppresses pigmentation genes and shifts the production of dark eumelanin toward reddish-yellow pheomelanin.
The source notes that there is no scientific evidence of a link between cats' coloration and their cognitive abilities. No obvious negative effects on the animals' health or mental well-being have been identified for this mutation either. Both papers were published in the journal Current Biology.
