Abstract
Avena maroccana (2n = 4x = 28) and A. sativa (2n = 6x = 42) are allopolyploids. Reconstructions from electron micrographs of synaptonemal complexes in serial sections of pollen mother cells showed that associations at zygotene and subsequent stages of meiosis are confined to homologous chromosomes only, with the result that only bivalents are generated. Such “classical” behaviour contrasts sharply with that in allopolyploids of wheat, Lolium and Scilla. In these pairing at zygotene involves homoeologous as well as homologous chromosomes, generating not only bivalents but multivalents which are “resolved” to bivalents prior to first metaphase.
An analysis is presented, also, of structural and genetic factors which influence the distribution of pairing within and between chromosomes at zygotene in the Avena species.
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Jones, M., Rees, H. & Jenkins, G. Synaptonemal complex formation in Avena polyploids. Heredity 63, 209–219 (1989). https://doi.org/10.1038/hdy.1989.94
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DOI: https://doi.org/10.1038/hdy.1989.94
