by Marina KHOLODOVA, Cand. Sc. (Biol.), leading research associate, A.N. Severtsev Institute for Problems of Ecology and Evolution, Russian Academy of Sciences (RAS)
Now why waste time and effort in studying the genetic diversity of wild animals? Is this relevant for their present and future? Such questions have been asked time and again. Why not just protect populations of rare species even if their initial progenitors were few in number-just several individuals?
European bisons (aurochs) are an excellent example illustrating what might seem to be at first sight the small significance of genetic diversity in the animal kingdom. By the onset of the 20th century there were only a few individuals of them, while their present population of three thousand comes from only twelve ancestors. That is why the genetic diversity of the newly reproduced population of aurochs is but very small. Our optimism in the initial period of the struggle for their numbers is giving way to concern about the future welfare of this species.
Such signs as the diminishing survival value of youngsters as well the incidence of diseases detected by Russian and Polish zoologists (caused by microorganisms, these diseases were considered not pathogenic before) go to show that the viability of aurochs whose gene pool is much depleted is declining. Today many facts point to this interdependence. It is particularly evident in rare species and small populations (cheetah, isolated groups of wolves, etc.). The matter involves not only the above negative aftereffects for the newly born younglings (lower weight, resistance to infections). The depleted gene pool also tells on different aspects of the reproduction process-from faulty spermatogeny in males to deviations in the normal sexual behavior and mating. Small isolated populations become prone to inbreeding and incest, something that worsens the animals' morphophysiological characteristics. In some species males come to be superior in numbers amongst ... Read more