YOU might expect a gerbil to end up inside a snake. But part of a snake ending up in a gerbil?
A small chunk of snake DNA has indeed turned up in wild gerbils, and it could one day show up in a host of other species too. Known as a 鈥渟hort interspersed element鈥� (SINE), it belongs to a class of non-coding DNA called retroposons, which are frequently copied and pasted from one location to another within an animal鈥檚 genome.
The clue to how it got into gerbils came when Oliver Piskurek and Norihiro Okada of the Tokyo Institute of Technology in Yokohama, Japan, analysed the genome of the taterapox virus, which affects African gerbils. They found the unmistakable signature of a SINE from the poisonous carpet viper (Proceedings of the National Academy of Sciences, ), and conclude that the taterapox virus originally infected the snake, inadvertently incorporated the snake鈥檚 SINE, and then infected the gerbils.
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The DNA is unlikely to incorporate into the gerbil genome, as gerbils do not carry the required genetic pasting mechanism, Piskurek says. The , and the SINE could pass into the genomes of these animals if the taterapox virus jumps species again. 鈥淭his is new,鈥� Piskurek says. 鈥淚t can definitely be a method of retroposon transfer between phylogenetically unrelated species.鈥�
