Sex-specific crossover distributions and variations in interference level along Arabidopsis thaliana chromosome 4

Abstract

In many species, sex-related differences in crossover (CO) rates have been described at chromosomal and regional levels. In this study, we determined the CO distribution along the entire Arabidopsis thaliana Chromosome 4 (18 Mb) in male and female meiosis, using high density genetic maps built on large backcross populations (44 markers, .1,300 plants). We observed dramatic differences between male and female map lengths that were calculated as 88 cM and 52 cM, respectively. This difference is remarkably parallel to that between the total synaptonemal complex lengths measured in male and female meiocytes by immunolabeling of ZYP1 (a component of the synaptonemal complex). Moreover, CO landscapes were clearly different: in particular, at both ends of the map, male CO rates were higher (up to 4-fold the mean value), whereas female CO rates were equal or even below the chromosomal average. This unique material gave us the opportunity to perform a detailed analysis of CO interference on Chromosome 4 in male and female meiosis. The number of COs per chromosome and the distances between them clearly departs from randomness. Strikingly, the interference level (measured by coincidence) varied significantly along the chromosome in male meiosis and was correlated to the physical distance between COs. The significance of this finding on the relevance of current CO interference models is discussed.

Pairing and synapsis in wild type Arabidopsis thaliana

“…Thus, SC length differs significantly between male and female meiocytes in mouse and human, paralleling variations in the foci number of the protein MLH1, which is involved in the process of reciprocal recombination (Lynn et al 2002, Tease & Hulten 2004. Sex differences in SC length have also been reported in zebrafish, Dendrocoelum lacteum and others (for references see Kleckner et al 2003), and recently for chromosome 4 of A. thaliana (Drouaud et al 2007). On these grounds, one would expect that the SC length/DNA content in different plant species would also be positively related to their mean recombination rates (centimorgans per megabase, cM/Mb), and effectively this is found (see Table 3).…”

Recombination patterns reveal information about centromere location on linkage maps

“…Crossover interference is a common phenomenon, but varies between sexes (Drouaud et al . ), among species (Segura et al . ) and even among chromosomes within a genome (Lian et al .…”

Elite durum wheat genetic map and recombination rate variation in a multiparental connected design

“…Both environmental (temperature and other stress conditions, Jain 1957) and genetic factors (genetic proximity of the parents, Modrich and Lahue 1996, presence of regulatory factors, Yandeau-Nelson et al 2006, sex, Moen et al 2004Drouaud et al 2007, gene density and percentage of GC residues, Schnable et al 1998;Paigen et al 2008) have been reported to affect recombination rate. On wheat, the crossover frequency increases from centromeres to the telomeres (Lukaszewski and Curtis 1993;Akhunov et al 2003;See et al 2006).…”