The tiny Antarctic midge, a wingless black fly less than a quarter of an inch long, has the smallest insect genome ever sequenced with just 99 million base pairs of nucleotides, researchers said.
Living in deep freeze as larvae for two winters, the insects emerge for just seven to 10 days to eat algae and bacteria and to mate before dying, Live Science reported. In comparison to the midge's 99 million, a body louse has 105 million base pairs of nucleotides, while the twisted-wing parasite has 108 million.
The midge's genome is short on so-called "junk DNA," the name for repeating DNA sequences that don't code protein but are vital to regulate genes.
"It has really taken the genome down to the bare bones and stripped it to a smaller size than was previously thought possible," said study co-author David Denlinger of The Ohio State University, as quoted by the AFP.
The fly has an incredible capacity to survive in larvae form even after losing up to 70 percent of its body water, possibly due to its plentiful aquaporins, which are genes that dictate how water moves in and out of cells.
"They look like dried-up little raisins, and when we pour water on them they plump up and go on their merry way," Denlinger said in a statement quoted by Live Science. "Being able to survive that extreme level of dehydration is one of the keys to surviving low temperatures. This midge has some mechanism that enables it to both be dehydrated and stay alive, with its cells functioning normally."
Comprising 13,500 functional genes, the midge genome has many genes that are instrumental in development but very few related to a sense of smell.
The new study documenting the Antarctic midge's genome was published today in Nature Communications.
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