CHICAGO, Feb. 2 (Xinhua) -- Thanks to its tumultuous evolutionary history, the house dust mite has developed a new way to protect its genome from internal disruptions, a genetic study suggests.
Researchers sequenced the DNA and the RNA of the American house dust mite, Dermatophagoides farinae. Then they looked at the populations of small RNA molecules encoded there.
They found that house dust mites do not have Piwi proteins or the associated small RNAs that most animals use to control transposable elements. Instead, dust mites have replaced the Piwi pathway with a completely different small RNA mechanism that uses small-interfering RNAs. The dust mite genome also encodes a protein that can amplify small-interfering RNAs.
"We believe that the evolution of this novel mechanism to protect genomes from transposable elements is linked to the unusual evolution of the dust mite," said Pavel Klimov, an associate research scientist in the University of Michigan (UM) Department of Ecology and Evolutionary Biology and co-author of the study.
"These animals evolved from parasitic ancestors. Frequently, the transition to parasitism is associated with dramatic genetic changes, a legacy carried by the dust mite when it moved back to a free-living lifestyle."
House dust mites are ubiquitous inhabitants of human dwellings, thriving in the mattresses, sofas and carpets of even the cleanest homes. They are the primary cause of indoor allergies in humans, affecting up to 1.2 billion people worldwide.
The study has been published on January 29 in the journal PLOS Genetics.
