Loss of complementation and the logic of two-step meiosis.
Meiosis is usually a two-step process: two divisions preceded by a duplication. One-step meiosis, a single division without prior replication, is a more logical way to produce haploid gametes; moreover, one-step meiosis leads to higher variabilty in the progeny than two-step meiosis. Yet one-step meiosis is very rare in nature, and may not even exist at all. I suggest that this is because one-step meiosis, in contrast to two-step meiosis, can be easily invaded and replaced by asexual reproduction. I discuss why other existing peculiar forms of division leading to the production of haploid gametes, but not one-step meiosis, have the same effect as two-step meiosis.
Département de Biologie, Section Ecologie et Evolution, Université de Fribourg, Fribourg, Switzerland. marco.archetti@unifr.ch
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D000818:Animals; D005075:Biological Evolution; D056890:Eukaryota / Q000235:genetics; D040582:Inheritance Patterns / Q000235:genetics; D008540:Meiosis / Q000235:genetics*; D008957:Models, Genetic; D011003:Ploidies; D011898:Ranidae / Q000235:genetics; D011995:Recombination, Genetic / Q000235:genetics; D012098:Reproduction / Q000235:genetics*; D012100:Reproduction, Asexual / Q000235:genetics