Crossovers Get a Boost in Brassica Allotriploid and Allotetraploid Hybrids

Meiotic crossovers are necessary to generate balanced gametes and to increase genetic diversity. Even if crossover number is usually constrained, recent results suggest that manipulating karyotype composition could be a new way to increase crossover frequency in plants. In this study, we explored th...

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Bibliographic Details
Published in:The Plant cell 2010-07, Vol.22 (7), p.2253-2264
Main Authors: Leflon, Martine, Grandont, Laurie, Eber, Frédérique, Huteau, Virginie, Coriton, Olivier, Chelysheva, Liudmila, Jenczewski, Eric, Chèvre, Anne-Marie
Format: Article
Language:English
Subjects:
Brassica - cytology
Brassica - genetics
Chromosomes
Crossovers
Diploidy
Genetic diversity
Genetic mapping
Genetics
Genomes
Hybridity
Hybridization, Genetic
Hybrids
Karyotypes
Karyotyping
Life Sciences
Linkage groups
Meiosis
Plants
Plants genetics
Prophase
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Summary:Meiotic crossovers are necessary to generate balanced gametes and to increase genetic diversity. Even if crossover number is usually constrained, recent results suggest that manipulating karyotype composition could be a new way to increase crossover frequency in plants. In this study, we explored this hypothesis by analyzing the extent of crossover variation in a set of related diploid AA, allotriploid AAC, and allotetraploid AACC Brassica hybrids. We first used cytogenetic methods to describe the meiotic behavior of the different hybrids. We then combined a cytogenetic estimation of class I crossovers in the entire genome by immunolocalization of a key protein, MutL Homolog1, which forms distinct foci on meiotic chromosomes, with genetic analyses to specifically compare crossover rates between one pair of chromosomes in the different hybrids. Our results showed that the number of crossovers in the allotriploid AAC hybrid was higher than in the diploid AA hybrid. Accordingly, the allotetraploid AACC hybrid showed an intermediate behavior. We demonstrated that this increase was related to hybrid karyotype composition (diploid versus allotriploid versus allotetraploid) and that interference was maintained in the AAC hybrids. These results could provide another efficient way to manipulate recombination in traditional breeding and genetic studies.
ISSN:1040-4651
1532-298X
DOI:10.1105/tpc.110.075986