The regulation of meiotic crossover distribution: a coarse solution to a century-old mystery?

Girard, Chloé; Zwicker, David; Mercier, Raphaël

doi:10.1042/bst20221329

Cited by 19 publications

(16 citation statements)

References 88 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is consistent with a prediction made already in the late 1930s ( 30 , 31 ) that shorter chromosomes have greater likelihood of forming bivalents in neoautopolyploid meiosis due to the positive correlation between chromosome length and cross-over number. This trend is also consistent with models for how HEI10 dosage affects cross-over rates and spacing, which has been explained recently with a “coarsening” model: HEI10 loads on chromosomes initially at similar levels per µm axis length, but as meiosis progresses, foci congeal by accumulating HEI10 from neighboring regions, leading to progressively wider spacing of larger and larger foci, the largest of which ultimately yield cross-overs in a pattern fitting with cross-over interference ( 39 , 60 ). In our lines, HEI10 dosage is reduced, suggesting that the above trends are explained because the smaller chromosomes load less HEI10 simply because they are shorter.…”

Section: Discussionsupporting

confidence: 87%

Partial cytological diploidization of neoautotetraploid meiosis by induced cross-over rate reduction

Gonzalo

Parra-Nuñez

Bachmann

et al. 2023

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Polyploids, which arise from whole-genome duplication events, have contributed to genome evolution throughout eukaryotes. Among plants, novel features of neopolyploids include traits that can be evolutionarily or agriculturally beneficial, such as increased abiotic stress tolerance. Thus, in addition to being interesting from an evolutionary perspective, genome duplication is also increasingly recognized as a promising crop improvement tool. However, newly formed (neo)polyploids commonly suffer from fertility problems, which have been attributed to abnormal associations among the multiple homologous chromosome copies during meiosis (multivalents). Here, we test the long-standing hypothesis that reducing meiotic cross-over number may be sufficient to limit multivalent formation, favoring diploid-like bivalent associations (cytological diploidization). To do so, we developed Arabidopsis thaliana lines with low cross-over rates by combining mutations for HEI10 and TAF4b . Double mutants showed a reduction of ~33% in cross-over numbers in diploids without compromising meiotic stability. Neopolyploids derived from the double mutant show a cross-over rate reduction of about 40% relative to wild-type neotetraploids, and groups of four homologs indeed formed fewer multivalents and more bivalents. However, we also show that the reduction in multivalents comes with the cost of a slightly increased frequency of univalents and that it does not rescue neopolyploid fertility. Thus, while our results do show that reducing cross-over rates can reduce multivalent frequency in neopolyploids, they also emphasize that there are additional factors affecting both meiotic stability and neopolyploid fertility that will need to be considered in solving the neopolyploid fertility challenge.

show abstract

Section: Discussionsupporting

confidence: 87%

Partial cytological diploidization of neoautotetraploid meiosis by induced cross-over rate reduction

Gonzalo

Parra-Nuñez

Bachmann

et al. 2023

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…We further investigated whether a relaxation of CO interference (COI) could account for the distinctive patterns of CO distribution observed. COI is the tendency of COs to form farther away from one another along the chromosome than would be expected by chance (reviewed in Girard et al 2023 ). This analysis was conducted by fitting the relative positions of COs to a gamma distribution and by analyzing of the coefficient of coincidence (CoC) (see Materials and Methods, supplementary table S6, Supplementary Material online).…”

Section: Resultsmentioning

confidence: 99%

Multiple Genomic Landscapes of Recombination and Genomic Divergence in Wild Populations of House Mice—The Role of Chromosomal Fusions and Prdm9

Marín-García,

Álvarez-González,

Marín-Gual

et al. 2024

Molecular Biology and Evolution

View full text Add to dashboard Cite

Chromosomal fusions represent one of the most common types of chromosomal rearrangements found in nature. Yet, their role in shaping the genomic landscape of recombination and hence genome evolution remains largely unexplored. Here, we take advantage of wild mice populations with chromosomal fusions to evaluate the effect of this type of structural variant on genomic landscapes of recombination and divergence. To this aim, we combined cytological analysis of meiotic crossovers (COs) in primary spermatocytes with inferred analysis of recombination rates based on linkage disequilibrium using single nucleotide polymorphisms. Our results suggest the presence of a combined effect of Rb fusions and Prdm9 allelic background, a gene involved in the formation of meiotic double strand breaks and postzygotic reproductive isolation, in reshaping genomic landscapes of recombination. We detected a chromosomal redistribution of meiotic recombination towards telomeric regions in metacentric chromosomes in mice with Robertsonian (Rb) fusions when compared to non-fused mice. This repatterning was accompanied by increased levels of CO interference and reduced levels of estimated recombination rates between populations, together with high levels of genomic divergence. Interestingly, we detected that Prdm9 allelic background was a major determinant of recombination rates at the population level, whereas Rb fusions showed limited effects, restricted to centromeric regions of fused chromosomes. Altogether, our results provide new insights into the effect of Rb fusions and Prdm9 background on meiotic recombination.

show abstract

“…The distribution of COs, a topic of current interest in meiotic research, was thoroughly reviewed in this journal [ 139 ]. However, a brief summary is pertinent.…”

Section: Synapsis and Crossover Distributionmentioning

confidence: 99%

The molecular machinery of meiotic recombination

Chen,

Weir

2024

Biochemical Society Transactions

View full text Add to dashboard Cite

Meiotic recombination, a cornerstone of eukaryotic diversity and individual genetic identity, is essential for the creation of physical linkages between homologous chromosomes, facilitating their faithful segregation during meiosis I. This process requires that germ cells generate controlled DNA lesions within their own genome that are subsequently repaired in a specialised manner. Repair of these DNA breaks involves the modulation of existing homologous recombination repair pathways to generate crossovers between homologous chromosomes. Decades of genetic and cytological studies have identified a multitude of factors that are involved in meiotic recombination. Recent work has started to provide additional mechanistic insights into how these factors interact with one another, with DNA, and provide the molecular outcomes required for a successful meiosis. Here, we provide a review of the recent developments with a focus on protein structures and protein–protein interactions.

show abstract

The regulation of meiotic crossover distribution: a coarse solution to a century-old mystery?

Cited by 19 publications

References 88 publications

Partial cytological diploidization of neoautotetraploid meiosis by induced cross-over rate reduction

Partial cytological diploidization of neoautotetraploid meiosis by induced cross-over rate reduction

Multiple Genomic Landscapes of Recombination and Genomic Divergence in Wild Populations of House Mice—The Role of Chromosomal Fusions and Prdm9

The molecular machinery of meiotic recombination

Contact Info

Product

Resources

About