Most of the Homoeologous Pairing at Metaphase I in Wheat-Rye Hybrids Is Not Chiasmatic
AUTOR(ES)
Orellana, Juan
RESUMO
The use of telomeric C-bands in wheat-rye hybrids has made it possible to distinguish three types of wheat-wheat (1BL) and wheat-rye associations (a, end-to-end extremely distal; b, end-to-ed distal; and c, interstitial) between homoeologous chromosomes at different metaphase I stages (early, middle and late) and also to estimate the actual recombination frequencies for such associations at anaphase I. There was a decrease of the a and b association frequencies during the different metaphase I stages, whereas the c type remained without variation in all stages. A good fit between the frequencies of c associations at metaphase I and the number of recombinant chromosomes at anaphase I, assuming a maximum of one chiasma per bond, was found; however, there was no correspondence between metaphase I and anaphase I data when all associations (a + b + c) were considered. In addition, rye-rye homologous pairing was observed at metaphase I, but no evidence for rye-rye recombination was found at anaphase I. The results indicate that most of end-to-end (a and b) homoeologous and nonhomologous associations are actually nonchiasmatic and are a remnant of prophase pairing.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1202680Documentos Relacionados
- Mapping of a Wheat-Rye Translocation
- Mathematical Comparison of Homologous and Homoeologous Chromosome Configurations and the Mode of Action of the Genes Regulating Pairing in Wheat
- Chromosome Differentiation and Pairing Behavior of Polyploids: An Assessment on Preferential Metaphase I Associations in Colchicine-Induced Autotetraploid Hybrids within the Genus Secale
- Statistical Analysis of Chromosome Pairing in Interspecific Hybrids. I. the Probability Distributions
- Pairing Competition between Identical and Homologous Chromosomes in Autotetraploid Rye. I. Submetacentric Chromosomes