Il ruolo della partenogenesi nei serpenti

Abstract

Parthenogenesis, or the production of embryos from unfertilized eggs, is a form of reproduction that occurs predominantly in different taxa of invertebrates where various types of such reproduction are recognized. Some animal species consist exclusively, or nearly so, of females that reproduce by parthenogenesis, generation after generation; others tend to alternate between parthenogenic and sexual generations or always have the ability to reproduce in both ways. Among vertebrates, parthenogenesis is a rare phenomenon and true parthenogenetic lineages can only be found in reptiles. Except for a single species which consists entirely of parthenogenetic females, snakes show the greatest amount of cases where parthenogenesis occurs occasionally in species that normally reproduce sexually (facultative or occasional parthenogenesis). Although some cases of snakes suspected of parthenogenetic reproduction have been reported in the past, the first documentation of facultative parthenogenesis (FP) occurred in 1997, following the application of molecular methods for parentage analyses. Since then, it has been described in different species of both viviparous and oviparous snakes. These cases have received a lot of scientific attention because, on the one hand, they can allow a better understanding of the general mechanisms that lead to parthenogenesis, on the other hand they can have important consequences for the breeding programs of reptiles. However, the evolutionary and adaptive role of FP in snakes, as well as its real diffusion in nature, requires further investigation in future studies.