Vampire bats' 'missing' genes may help them survive on all-blood diet

Vampire bats eat a blood-only diet, which is high in protein but low in other nutrients. The Scientist Magazine reports that a new study suggests that the flying mammals may have "missing" genes. This could explain why they can survive on only blood meals, which are taken from the victims' open wounds at night.
Researchers compared the genomes of Desmodus rotundus (the common vampire bat) and 25 other bat species in a new study. It was posted to the bioRxiv preprint database on Oct. 19. The analysis showed that D.rotundus does not have functional copies of 13 genes found in other bat species. This means that the missing genes are either absent completely or can't be produced by the vampires. Michael Hiller, co-author of the study and a geneticist at Germany's LOEWE Centre for Translational Biodiversity Genomics, explained to The Scientist.

It turns out that vampire bats may be able to benefit from losing 13 genes. According to the study that has not been peer reviewed, losing these genes could help vampire bats extract nutrients from their blood in ways other bats cannot.

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Two of the genes missing drive insulin secretion from the pancreas. Insulin is a hormone that regulates blood sugar levels by moving glucose into cells. Hiller explained to The Scientist that past studies have shown that vampire bats produce very little insulin. This is because their blood contains very few carbohydrates. He said that the lack of insulin secretion could help bats preserve the sugar they consume by keeping it in their bloodstream.

In their study, the authors also noted that the vampire bat genome was missing a REP15 gene. This gene is normally activated in the cells in the gastrointestinal tract. This gene could decrease the iron that can be absorbed into bats' gastrointestinal cells by increasing the number of "doors" through which iron can move on the cell surface. The study authors stated that iron-laden cells would turn over faster than other bats. This would help vampires eliminate all iron from their diets and prevent metal poisoning.

The Scientist also reported that CTRL, another missing gene, would normally reduce the activity of trypsin (an enzyme involved in protein digest and absorption), The Scientist reported. Without CTRL, vampire bats are likely to have a higher level of trypsin activity, which helps them break down their protein-rich blood meals.

The authors pointed out that several of the genes missing appear to be related to bats' metabolism and digestion, while others relate to their cognitive abilities and vision. Some of these genes are unknown to have any effect on bat physiology, and warrant further research.

The three missing genes were discovered through research published in the journals Molecular Biology and Evolution and Proceedings of the Royal Society. These genes code for taste receptors that detect sweet and sour flavors.

The Scientist Magazine has more information about the missing genes of vampire bats.

Original publication on Live Science