A New Model for Homologous Chromosome Pairing

Abstract

SUMMARYIt is proposed that chromosome pairing may result from the fortuitous juxtaposition of homologues by the congressive adjustments of chromosome positions during mitotic metaphase alignment. (Some unknown mechanism for stirring of chromosomes may exist in organisms with zygotic meiosis). During this juxtaposition it is suggested that numerous elastic physical connections are formed between corresponding sites of homologues and that these persist through later stages or even many cell cycles, often so stretched that little or no evidence of pairing can be found, until meiotic prophase. At this time these hypothetical elastic physical connections may function to bring the chromosomes they connect sufficiently close together for the formation of the synaptonemal complex.Photomicrographs of the premeiotic mitosis in maize illustrate peculiar features typical of this division and in support of the hypothesis outlined above.