Kopecký, D., Havránková, M., Loureiro, J., Castro, S., Lukaszewski, A.J., Bartoš, J., Kopecká, J., Doležel, J.
CYTOGENETIC AND GENOME RESEARCH
129:
162-172,
2010
Keywords:
Chromosome introgression, Festuca, Flow cytometry, Genome size estimation, Homoeologous recombination, Karyotype, Lolium
Abstract:
Crossing over-based recombination is a powerful tool for
generating new allelic combinations during sexual reproduction.
It usually occurs between homologous chromosomes.
However, under some conditions, homoeologues
may also be capable of crossing over. Whether homologous
and homoeologous crossovers are equivalent and governed
by the same rules has never been established. Here we report
on chromosome distribution of homoeologous crossovers
in a unique system of Festuca ! Lolium hybrids. Unlike
in most other hybrids, in these intergeneric hybrids, homoeologous
chromosomes are capable of pairing and crossing
over with frequencies approaching that of homologues.
At the same time, genome divergence makes cytological
detection of chromosome recombination feasible. We
analyzed the distribution of homoeologous recombination
along individual chromosomes in a complete set of intergeneric single chromosome substitutions from F. pratensis into
tetraploid L. multiflorum . Homoeologous recombination
sites were not evenly distributed along the chromosomes,
being concentrated in intercalary regions of the arms and
reduced in proximal and distal regions. Several recombination
hotspots and cold spots were found along individual
chromosomes and the recombination was not affected by
the presence of a secondary constriction. Our results indicate
that despite the uneven distribution of homoeologous
recombination, introgression of any part of the F. pratensis
genome into L. multiflorum is feasible.
Fulltext: contact IEB authors
IEB authors: Jan Bartoš,
Jaroslav Doležel,
Miroslava Havránková,
David Kopecky
Čeština
English