The Evolution of Meiosis From Mitosis

accounted for. We next ask what selective pressures might have favored the acquisition of homolog synapsis. The conclusion is surprising: the initial function of chromosome pairing was to limit, not enhance, recombination. Finally, we review the evidence that much of the molecular machinery required for the initial forms of homolog pairing probably existed in proto-eukaryote unicellular forms prior to the evolution of meiosis and therefore could have been readily ‘‘recruited’’ for the new role. Some experimental tests of the hypothesis are proposed.