Evolutionary Origin of Recombination during Meiosis | Semantic Scholar

Evidence is presented that archaeal mating was the likely ancestral precursor to eukaryotic meiotic sex, and evolution in complexity was likely part of a general protective response to DNA damaging reactive oxygen species produced by the proto-mitochondria during the prokaryotic to eUKaryotic transition.

Rather than providing selective advantages through reproduction, sex could be thought of as a series of separate events which combines step-by-step some very weak benefits of recombination, meiosis, gametogenesis and syngamy.

That a benefit exists if the dividing cell(s) form a simple colony of the resulting haploids for some time after reproduction is explored here and shown to further increase the benefits of the landscape smoothing process.

This paper suggests, based on the energetic aspect of genome organization, that the emergence of eukaryotes was promoted by the establishment of an efficient energy-converting organelle, such as the mitochondrion, which was acquired by the endosymbiosis of ancient α-purple photosynthetic Gram-negative eubacteria that reorganized the prokaryotic metabolism of the archaebacterial-like ancestral host cells.

Gene sequence data strongly support a monophyletic origin of the mitochondrion from a eubacterial ancestor shared with a subgroup of the alpha-Proteobacteria and raise the possibility that this organelle originated at essentially the same time as the nuclear component of the eukaryotic cell rather than in a separate, subsequent event.