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Indian black tigers have unusually thick stripes due to genetic mutation

Tiger with abnormal fur.

Tigers are depicted in a wildlife park in eastern India. variety of coats fashion… In particular, some cats have very thick black stripes.… Now, a group of geneticists from India and the United States have identified a genetic mutation in the tiger troupe that explains why some of them are so dark.

Tigers are pseudo-Melanistic, which means they have wide, merging stripes along their bodies. (This should not be confused with leucistic tigers, which are white with black stripes due to another unusual trait. leucism.) From some angles, pseudo-Melanin tigers may appear mostly black, hence their nickname “black” tigers. More than a third of the tigers in the Similipal Tiger Reserve are pseudo-Melanistic. A team of researchers led by Vinay Sagar of the Tata Institute for Basic Research conducted a genetic survey of 85 tigers in four regions.r to find out how these animals differ at the molecular level. Their findings were published this month in Proceedings of the National Academy of Sciences.

“Pseudo-Melanistic tigers have a mutation in their Taqpep gene – like humans, tigers have two copies of each gene, and both copies are mutated in pseudo-Melanistic tigers — and without any Taqpep, the patterning process is defective, leading to expansion and random occurrence … merging bands “, co-author Greg Barsh, a geneticist at Stanford University and the HudsonAlpha Biotechnology Institute, said in an email to Gizmodo.

Royal cheetah spots.

The team’s analysis showed that all pseudo-Melanistic cats had one variant of the nucleotide in their genetic code that appeared to alter a specific gene. This gene is calledd Transmembrane aminopeptidase Q (Takpep for brevity), and it is the same gene that is responsible for spots and stripes in striped cats and cheetahs, according to members of the current research group. discovered back in 2012

In tigers, a single nucleotide of cytosine was replaced with thymine, which changed the way Takpep the gene behaved. Once recessively inherited versions of genes developed tabby marks and made royal cheetahsshaky Takpeps in tigers, they appear blacker than orange.

Eight subspecies of tigers are known, but three of them have been declared extinct. according to the US Fish and Wildlife Service… All existing subspecies are endangered, and a few captive tigers struggle with the problems that arise when a small number of animals try to maintain the genetic diversity of an entire species. This is why conservation is not as easy as breeding as many endangered animals as far as possible

“Counting the number of species is not enough,” said Uma Ramakrishnan. scientist at the Tata Institute for Basic Research, in an email to Gizmodo. “In general, the number of tigers has increased. But many tiger populations throughout their range remain small and isolated and therefore prone to genetic drift or random changes in allele frequencies and inbreeding. We are still looking into the future of these populations. ”

Recessive Takpep phenotypes were present in more than half of the tigers living in the Similipal Reserve. Even white tigers can have this trait, which makes some animals a bit like marbled bread. Tiger the population appears to be inbred, which may explain the presence of a sign in very many animals.

Tigers of different phenotypes.

“Most color mutations tend to affect the entire body, such as albinism or melanism, so mutations that affect color patterns are particularly interesting scientifically because they help us learn more about developmental biology,” said Barsh.

The wide stripe trait is not necessarily harmful: the research team said that if this trait was not just due to inbreeding, then it could be due to some evolutionary advantage. They refer to melanistic leopards, which are more likely to appear in dark, dense rainforests than in drier ones. open environment. If a similar situation occurs with the Similip Tigers, they may lose some of their orange in order to better merge with it. jungle underbrush.

Whatever the evolutionary logic behind the tiger stripes, it’s a reminder that animal fur should never look too thick.

Read more: Yellow dog coats descended from ancient canines that separated from wolves 2 million years ago


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