Thanks to a crowdfunding effort, a pair of scientists have sequenced the genome of one of the internet's most famous cats, Lil Bub.

The furry celebrity, known for its extra toes and tongue that hangs out of its mouth, is the subject of new research that probed the cat's genetic abnormalities.

A Genetic Study Of Lil Bub

In a paper that appears in the pre-print site bioRxiv, geneticists identified two mutations that caused the cat's unique but endearing traits. The first one is a mutation of the Sonic hedgehog gene, which is responsible for Lil Bub's extra toes. The Ernest Hemingway Home and Museum in Key West, Florida is famously populated with polydactyl cats, a genetic condition that causes the animals to be born with extra toes.

The second is a variation of TNFRSF11A, a gene that is associated with osteopetrosis, a rare inherited disease that causes increased bone density, in humans and mice. The disease is also associated with slow growth and short stature.

"At first, you're thinking Lil Bub's polydactyly and her limb shortness are all part of the same syndrome," explained Leslie Lyons, an expert on cat genetics from the University of Missouri and a co-author of the study, to Science Magazine. "Then you start to tease it apart and you realize, no, she has Sonic hedgehog mutations that have nothing to do with the osteopetrosis issue that's going on. It was like, 'Wow, that's kind of weird, the cat has two different rare mutations.'"

Orsolya Symmons of the University of Pennsylvania added that the discovery is significant because genetic osteopetrosis has never been described in cats. Knowing that the mutation also exists among cats could lead to better therapy for human patients diagnosed with osteopetrosis.

The researchers are hoping to publish their findings in a peer-reviewed journal in the future and encourage funding for cat research.

"In human genetics, there's a still a huge number of variants of unknown significance, which basically means you don't know if they're benign or not," stated Lyons. "That's one of the things our project is trying to do. If you look at the genetic information in cats and dogs, that might tell you a particular mutation is found all the time in cats and they're perfectly fine, so it probably is a benign mutation."

Lil Bub Does Science

The study was funded through the Experiment website. The researchers raised more than $8,000 to sequence the famous cat's whole genome.

This is not the first time that Lil Bub has lent its paw to science. The internet sensation previously teamed up with Phase Genomics, AnimalBiome, and KittyBiome to study the bacteria that live inside the guts of animals. The effort has led to the discovery of 22 new kinds of bacteria, 13 of which were from the poo sample provided by Lil Bub.

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