Study Of Dust Mites Show That Reverse Evolution Is Genetically Possible
redOrbit Staff & Wire Reports – Your Universe Online
By studying dust mites, two University of Michigan biologists claim to have found evidence that contracts Dollo´s law — a long standing scientific belief claiming evolution is irreversible.
According to Pavel Klimov and Barry O´Connor of the Ann Arbor-based university´s Department of Ecology and Evolutionary Biology, the free-living dust mites that typically inhabit our homes evolved from parasites.
Those parasites,themselves, had evolved from free-living organisms millions of years ago.
That contradicts Dollo´s law — the commonly held but not universally accepted belief evolution only travels in one direction and that creatures cannot move backwards to less-evolved ones according to Geekosystem writer Ian Chant.
However, the law, named for a 19th century French paleontologist, has long been challenged by some scientists, arguing it “may be more of a set of guidelines — commonly applicable, certainly, but not without exceptions,” writes Chant.
Klimov and O´Connor claim to have discovered one such exception. They analyzed more than five dozen different hypotheses on the evolutionary relationships of the mites, Nature World News reported Saturday.
They then studied the DNA of over 700 different species of mites to develop an evolutionary history of the creatures, and discovered house mites were closely related to the Psoroptidia — parasites which live in the bodies of animals and birds. Furthermore, they found the immediate parasitic ancestors of house dust mites included skin mites (such as those that cause mange in livestock) and canine/feline ear mites.
In a statement issued Friday, Klimov called the results “surprising” and looked for feedback from colleagues before submitting their findings for publication.
“Parasites can quickly evolve highly sophisticated mechanisms for host exploitation and can lose their ability to function away from the host body,” he continued. “They often experience degradation or loss of many genes because their functions are no longer required in a rich environment where hosts provide both living space and nutrients. Many researchers in the field perceive such specialization as evolutionarily irreversible.”
“Our study is an example of how asking a purely academic question may result in broad practical applications,” added Connor. “Knowing phylogenetic relationships of house dust mites may provide insights into allergenic properties of their immune-response-triggering proteins and the evolution of gene encoding allergens.”
The study, which started in 2006 and was supported by a grant from the National Science Foundation, has been published in the journal Systematic Biology. More than 60 biologists in 19 different countries contributed to the work by collecting specimens for the study, according to the university.