Berlin: Modifying the adage 'Unity in Diversity' to 'Genetic Diversity makes populations immune to diseases,' a new study claims that host populations, who adapt to newer climate easily by making few variations in their genes, also become immune to common diseases. Researchers from the Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB) succeeded in demonstrating experimentally that genetic diversity makes populations more resistant to disease.
A team led by IGB researcher and evolutionary ecologist Dr Ramsy Agha investigated the evolution of fungal parasite Rhizophydium megarrhizum. This parasite infects the cyanobacterium species Planktothrix, which is prevalent in many freshwaters. The team exposed the parasite to host populations whose individuals were genetically identical to each other, and alternatively to populations comprised of different genetic variants. Since the fungus multiplies rapidly, roughly once a day, the scientists monitored its performance for a total period of 200 days.
"We wanted to observe evolutionary change in real time and under controlled conditions, to find out if and how quickly parasites adapt to genetically homogenous and diverse hosts," explained Dr Agha.The scientists permitted the adaptation of Rhizophydium megarrhizum, but kept the host populations in an evolutionary standstill. "We were able to show that the fungi adapt to genetically homogenous hosts very quickly, that is within just three months," Dr Agha told the Science Daily.
This adaptation is reflected in the fact that the parasites managed to adhere to the hosts and overcome their defence mechanisms more quickly, and were therefore able to reproduce more rapidly. If, on the other hand, the cyanobacteria were genetically diverse, these effects did not occur. The parasite failed to adapt, and the state of the disease remained unchanged. Genetic diversity in cyanobacteria evidently slows down the adaptation of the parasite, increasing their resistance to disease.
"Our findings are also significant for ecosystem research in general, because they help us to explain why a high degree of diversity in populations may be valuable for their preservation," said Dr Agha. (UNI)
