Vampire bats have an unusual diet that consists only of blood that is high in protein but lacks other nutrients. Now a new study suggests that “missing” genes may explain how the flying mammals survive on nothing but blood meals, hurled from their victims’ open wounds in the gloom and darkness of the night, It reported The Scientist Magazine.
In the new study, which was posted Oct. 19 to the preprint database bioRxiv, researchers compared the genome of the common vampire bat (Desmodus rotundus) with them from 25 other bat species. It showed the analysis D. rotundus missing functional copies of 13 gener appearing in the other bats; these missing genes are either completely absent in the vampires’ genome, or they contain so many mutations that they are unlikely to produce functional proteins, co-author of the study Michael Hiller, a genomicist at the LOEWE Center for Translational Biodiversity Genomics in Germany, told The Scientist.
And it turns out that vampire bats can benefit from dropping these 13 genes. Losing the genes can help them extract nutrients from blood in ways that other bats cannot, according to the study, which has not been peer-reviewed.
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For example, two of the missing genes drive the secretion of insulin the pancreas, where insulin is a hormone that regulates the amount of sugar in the blood by moving glucose into the cells. Previous studies have shown that vampire bat secretes a little insulin, which makes sense given that blood those drinks contain few carbohydrates, Hiller told The Scientist. This lack of insulin secretion can help bats save the little sugar they ingest by keeping that sugar available in the bloodstream, he said.
The vampire bat genome also lacked a gene called REP15, which is normally activated in the cells of the gastrointestinal tract, the authors noted in their study. Losing this gene is likely to increase the amount of iron that can slide into the bat’s gastrointestinal cells by increasing the number of “doors” that iron can pass through on the cell surface. These iron-loaded cells would therefore turn faster than in other bats, helping the vampires effectively get rid of all the iron acquired through their diet, thus avoiding metal poisoning, the study authors wrote.
Another missing gene, CTRL, would normally reduce the activity of trypsin, an enzyme involved in protein digestion and absorption, The Scientist reported. Without CTRL, trypsin activity is likely to increase in vampire bats, helping them break down their protein-heavy blood meals.
Several of the other missing genes appear to be involved in the bat’s digestion and metabolism, while others are related to the bat’s cognitive abilities and vision, the authors noted. And some of the missing genes have unknown effects on the physiology of the bat and warrant further investigation.
Three of the 13 missing genes had actually been revealed through previous research, published in the journals Molecular biology and evolution and Proceedings of the Royal Society B; these genes would normally encode taste receptors that detect sweet and bitter tastes that are largely absent from vampire bats’ diets.
Read more about the missing vampire bat genes in The Scientist Magazine.
Originally published on Live Science.