The human genome, a miracle of evolution, contains some 3.2 billion base pairs. That’s because humans do lots of stuff – we see, we taste, we smell, we talk, we poop, etc. According to researchers from Washington State University, the Antarctic midge genome has just 99 million base pairs – the smallest insect genome mapped to date.

The reason, they suspect, is a matter of survival.

“We suspect that it’s somehow an adaptation to the extreme environment,” said Washington State University assistant professor Joanna Kelley. “And it opens up a lot of interesting hypotheses to hopefully test by sequencing additional Antarctic organisms or sub-Antarctic organisms, because there are other flies, or Diptera, on some of the sub-Antarctic islands. We’re really interested to see whether or not they have similar genomes.”

Basically, the small fly’s harsh environment dictates what it needs and doesn’t need to survive. Its larvae take two winters to develop, during which it loses a substantial amount of body weight. It also must endure freezing temperatures, high winds, salty air and intense UV radiation, all to live for about a week.

Once it’s grown, it rarely travels far – it has no wings, and can’t go anywhere further than it can walk. In turn, they have fewer odor receptors (for example), because they don’t need to detect all that much.

Overall, Kelley says the genome the genome “opens up a lot of questions for me about genome evolution, and I’m looking at other related organisms to try and get at that question. What allows or inhibits a genome from being very large or small and what are the consequences of that?

“It’s a pretty exciting fly,” she said.