Genetic dissection of sexual reproduction in rice (Oryza sativa L.)

Abstract

Sexual reproduction is the most important step in increasing the genetic diversity of offspring. It is defined by two major events: meiosis and fertilization. Meiosis is a crucial event to form haploid spores and gametes, and is characterized by a single round of premeiotic DNA replication followed by two continuous rounds of chromosome segregation. Homologous recombination, an essential feature of meiosis, results in generating new haplotypes by shuffling alleles. Fertilization is achieved by the fusion of two gametes and produces new genotypes of diploid cell or zygote. In contrast, reproductive isolation contributes to establishing genetic stability of species, rather than genetic diversity, in most eukaryotes, and is achieved by various mechanisms, for example, the differential fitness of the gametophyte or zygote (Dobzhansky 1951; Stebbins 1958). Biological species are generally defined as groups of interbreeding populations that are reproductively isolated (Mayr 1942).