ISSN:
1432-0886
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Abstract In order to assess the genome homologies of a number of diploid and tetraploid species of Avena, two meiotic characters — mean chiasmata per cell and frequency of types of pairing configurations — have been studied in the species and in a number of diploid, triploid and tetraploid hybrids. The results indicate extensive structural differentiation of the genome of A. longiglumis from that which is common to the other diploids A. strigosa, A. brevis, A. hirtula, A. glabrata and A. wiestii. Structural differentiation is found also between the genomes of the three tetraploids A. vaviloviana, A. abyssinica and A. barbata. Chromosome pairing in triploid hybrids indicates the similarity of the genome in the A. strigosa group to one of those in the tetraploids and a partial but significant affinity with the other. These data, though derived from a very limited range of genotypes, lead to the conclusions that (a) structural differentiation of chromosomes may be common in the genus and important in its evolution, and (b) that current ideas on evolution of the polyploid species through simple allopolyploidy are unlikely to be true. The polyploids probably have a more complex origin in which autopolyploids or near autopolyploids and structural change of chromosomes have played a part.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00331899
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