Scientists find blood-feeding genes in bats
(ORDO NEWS) — The “bloody” diet of vampire bats required a complex whole-body adaptation and the shutdown of 13 genes associated with digestion, energy production and memory.
Contrary to popular legends, blood is far from being the most nutritious food. There are much fewer calories in it than in meat, and even more so fat, and the only warm-blooded animals that can survive solely on someone else’s blood is a small group of small bats, which are called vampire bats .
They live in Central and Latin America and at night they find sleeping birds or mammals ( including humans ), quietly bite through the skin, inject painkillers and anticoagulants – and drink a couple of tens of milliliters.
For an animal, this is usually a fairly small amount, but for the vampire himself, it is comparable to his own weight, and often it is not easy for him to even take off from the victim.
But blood is low in calories, and a vampire does not have to choose: a couple of days of fasting – and he will die from exhaustion altogether. These bloodsuckers really do not have to live, but to survive, and for this they have to turn off more than a dozen important genes for “ordinary” mammals.
Michael Hiller and his colleagues compared the genome of the common vampire Desmodus rotundus with the genomes of 26 other bat species, finding that as many as 13 genes, apparently related to adaptation to blood feeding, do not work in them.
Three genes code for taste buds, which are really not as necessary for a “bloody diet” as for animals that eat, for example, fruits or plant nectar.
Other disabled genes are associated with the production of insulin ( FFAR1 and SLC30A8 ) and the conversion of sugars into glycogen ( PPP1R3E ) and other molecules in which the body of a normal mammal stores energy reserves. In vampire bats, these genes don’t work, because they can’t possibly drink enough low-calorie blood to get a surplus and store it.
Also disabled are unnecessary genes responsible for the production of gastric juice ( ERN2 and CTRL ), which is needed to digest more diverse foods.
The REP15 gene , which is responsible for the absorption of iron in the intestines, also does not work, otherwise the bat would receive such amounts of this metal from the blood that would have a toxic effect on its body.
It is curious that one of the disabled genes can only be indirectly related to blood feeding: the authors of the work believe that, working in the brain, it stimulates the cognitive abilities of desmodus.
These bats are known for their “intelligence” and high sociality, which, again, helps to survive on an extremely poor blood diet. If necessary, they can regurgitate some of the extracted blood directly into the mouth of another vampire, sharing with him the deficient calories.
At the same time, desmoduses remember exactly who, with whom and when shared, and who did not, and in the future treat their neighbors accordingly.
It is possible that in order to form such a complex and long relationship, they needed to turn off one of the genes, CYP39A1 . In other animals, it weakens the connections between neurons, among other things, but in vampires it works, allowing them to become better friends .
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