Understanding the evolution of viviparity using intraspecific variation in reproductive mode and transitional forms of pregnancy.

ABSTRACT: How innovations such as vision, flight and pregnancy evolve is a central question in evolutionary biology. Examination of transitional (intermediate) forms of these traits can help address this question, but these intermediate phenotypes are very rare in extant species. Here we explore the biology and evolution of transitional forms of pregnancy that are midway between the ancestral state of oviparity (egg-laying) and the derived state, viviparity (live birth). Transitional forms of pregnancy occur in only three vertebrates, all of which are lizard species that also display intraspecific variation in reproductive phenotype. In these lizards (Lerista bougainvillii, Saiphos equalis, and Zootoca vivipara), geographic variation of three reproductive forms occurs within a single species: ovipar

SUBMITTER: Whittington CM 

PROVIDER: S-EPMC9064913 | biostudies-literature | 2022 Jun

REPOSITORIES: biostudies-literature