Recent research indicates that the tiny Antarctic midge fly has the smallest genome in insects, even smaller than that of a body louse.
Scientists suggest that the extreme Antarctic winter conditions may be responsible for the smaller genome of the midge fly.
The Antarctic midge is also called Belgica Antarctica and is found only in the remote Antarctica continent. The insect does not have wings and measures between 2 to 6 millimeters. The larval stage of the insect lasts for around two years during which it is frozen in the Antarctic ice and withstands temperature of as low as -40 degrees Celsius. At the larval stage, the midge can lose up to 70 percent of the body's water and can still survive.
The adults usually emerge in spring or winter and live for just over a week. The females mate during the first few days of life and then lay eggs just a few days after.
A group of international scientists have conducted a study, which has revealed that the genome of the Antarctic midge contains 99 million base pairs of nucleotides, which are the building blocks of DNA. The scientists suggest that the genome of the Antarctic midge is even smaller than that of a body louse, which has 105 million base pairs of nucleotides.
David Denlinger, Distinguished Professor of entomology and of evolution, ecology and organismal biology at The Ohio State University, who is the senior author of the study, says that the genome of the Antarctic midge does not include DNA segments and certain other elements, which are present in the genome of other insects. The lack of such elements in the genome may help the insect to survive in the extreme Antarctic conditions.
"It has really taken the genome down to the bare bones and stripped it to a smaller size than was previously thought possible. It will be interesting to know if other extremophiles - ticks, mites and other organisms that live in Antarctica - also have really small genomes, or if this is unique to the midge. We don't know that yet," says Denlinger.
The researchers are trying to understand the implications of why the Antarctic midge does not have the DNA segments found in other insects. The researchers are studying if the lack of certain DNA segments is responsible for the insect to survive in the dry and cold weather conditions of Antarctica.
The findings of the research have been published in the journal Nature Communications.
