Читать книгу Fundamentals of Conservation Biology - Malcolm L. Hunter Jr. - Страница 100

We have touched on the importance of genetic diversity already. To really understand the importance of genetic diversity, it is useful to think of genes as units of information rather than tangible things. As tiny aggregations of carbon, hydrogen, oxygen, nitrogen, and some other common elements, genes have little value in and of themselves. Indeed, when DNA is extracted from any organism and concentrated in the bottom of a test tube it appears as a small, sticky, gray, and rather unattractive blob. As sources of information, however, genes are clearly essential; they shape the synthesis of the biochemicals that control cellular activity and, ultimately, all biological activity and form. The capacity for genes to encode this information is stupendous; a typical mammal might have 100,000 genetic loci.

Of course, most of this wealth of genetic diversity is encapsulated in the diversity of species and their interspecific genetic differences. The key issue to address here is the distribution and diversity of alleles that characterize a species. Why is it important to maintain different versions of the same gene and, in many circumstances, to have them well distributed in a population dominated by heterozygotes rather than homozygotes? There are three basic answers: evolutionary potential, loss of fitness, and utilitarian values.