Genotypic characteristics of cyclic parthenogens and their obligately asexual derivatives.

摘要: Cyclic parthenogenesis is a mode of reproduction which involves the more or less regular alternation asexual and sexual reproduction. During phase life cycle individuals develop from unfertilized eggs as opposed to other forms asexuality in new somatic tissues. In organisms employing this latter breeding system timing varies immediately after zygote formation (polyembryony) until late adult (fission). Many asexuals also reproduce sexually hence employ very similar cyclic parthenogenesis. While distinction parthenogens may be hard justify on genetic criteria, their separation has long historical basis (von Siebold, 1857; Weismann 1893) founded unique ability produce both eggs. Bell (1982) advocated extending use term include alternate between obligate self-fertilization outcrossing. This seems unwise, for such consequences different those conventional Selfing leads rapid loss heterozygosity (Wright, 1969), while during apomictic maintained even amplified (Berger, 1976). On present review considers only traditional parthenogens.