By DPA
Hamburg : Asexual micro organisms continue to display an amazingly diverse ability to adapt to their ever-changing environment as they have over the past 100 million years, according to scientists who are baffled by these creatures’ non-sexual evolutionary change.
New research by scientists at the Max Planck Institute for Molecular Botanical Physiology in Potsdam, Germany, say they have discovered startling new evidence of adaptation to external environmental stimuli by asexual micro organisms.
Until now, it has been assumed that sexual transfer of genetic data is a necessary step in evolutionary adaptation. But the study of wheel-shaped micro-invertebrates called bdelloid rotifers shows they are no slouches when it comes to adapting to their environment without sexual relations with each other.
“Theory suggests it should be difficult for asexual organisms to adapt to a changing environment because genetic diversity can only arise from mutations accumulating within direct antecedents and not through sexual exchange,” says Dirk Hincha, writing in the journal Science.
“But in an asexual micro-invertebrate, the bdelloid rotifer, we have observed a mechanism by which such organisms could acquire the diversity needed for adaptation.”
It is the first time that such adaptation amongst asexual creatures has been demonstrated, he says.
“These organisms, living in puddles and water droplets, have diversified into 400 varieties to cope with varying environments, all of these changes by means of asexual reproduction,” he says.
“Gene copies most likely representing former alleles have diverged in function so that the proteins they encode play complementary roles in survival of dry conditions,” he explains.
“One protein prevents desiccation-sensitive enzymes from aggregating during drying, whereas its counterpart does not have this activity, but is able to associate with phospholipid bilayers and is potentially involved in maintenance of membrane integrity,” he adds.
The conclusion is that adoption of asexual reproduction could itself be an evolutionary mechanism for the generation of diversity.