The role of reproduction in the emergence and evolution of polyploids

Abstract

Castro, S., Loureiro, J.. 2014. The role of reproduction in the emergence and evolution of polyploid plants. Ecosistemas 23(3): 67-77. Doi.: 10.7818/ECOS.2014.23-3.09

Polyploidy, the heritable condition of having more than two sets of chromosome per nucleus, has long been recognized as a major mechanism in plant speciation, and is widespread in the evolutionary history of angiosperms. This phenomenon has been proposed as a mechanism of rapid sympatric speciation because new entities can arise in the population and theoretically achieve immediate reproductive isolation. Reproduction plays a central role being involved not only in the emergence of new cytotypes but also in their maintenance and subsequent dispersal. The production of unreduced gametes is currently considered as the main pathway for the emergence of new cytotypes despite the reduced information available about its frequency in natural populations. Under random mating, the establishment of neopolyploids is subjected to strong frequency-dependent selection; thus, their successful establishment will depend on a set of ecological features that increase the reproductive success and, consequently, the probability of the new formed polyploids to persist in the parental population. Theoretical models suggest that traits as the ability to (continuously) produce new cytotypes, their fecundity, life-history, competitive ability or niche differentiation are important features that determine the persistence of new formed polyploids. However, despite its importance, there are still few studies exploring ecological consequences of genome duplications. In this paper we review the role of reproduction in the emergence and establishment of new cytotypes, highlighting the questions that remain to be explored.