Why does this frog have so much snake DNA?

Why does this frog have so much snake DNA? Snakes are more closely related to people than they are to frogs, with the last snake-human-frog common ancestor living more than 300 million years ago. However, a recent DNA analysis suggested that in the last 85 million years, a particular gene has jumped from snakes to various species of frogs at least 54 times. The process of genetic material moving from the genome of one species to another is known as horizontal gene transfer.

In this case the gene in question (BovB) was probably transferred by a virus that picked it up while infecting snakes, and which was then transferred to frogs by a tick or some other parasite. This particular gene doesn’t seem to give frogs any evolutionary advantage, but another case of horizontal gene transfer between two coldwater fish species (herring and smelt) spread the ability to make antifreeze proteins that lower the temperature at which ice crystals start to form in their blood.

Link to the HGT Snake-Frog paper:
doi.org/10.1093/molbev/msac052

Link to the HGT Herring-Smelt paper: www.sciencedirect.com/science/article/pii/S0168952…

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