Histone acetylation and sex-specific recombination variation in Arabidopsis thaliana

Arabidopsis is characterized by heterochiasmy: indeed, it is reported that crossover (CO) rate and distribution vary between male and female meiosis. Chromosomes recombine at a higher rate in male than female meiosis (CO per cell: 11.1 vs 6.6). Furthermore, CO rates are high at the telomeric ends of the chromosomes in male meiosis and at proximal regions in female meiosis. Our research team investigated whether histone acetylation was determinant in heterochiasmy. To address this question, we analyzed chromosome-wide recombination frequency through SNP genotyping in populations derived from a T-DNA mutant (Atmcc1) characterized by increase in histone acetylation. Firstly, two F1 populations were generated by crossing Atmcc1 as male and female parent with Ler genotype as well as two F1 control populations (reciprocal crosses C24 x Ler). Afterwards, four BC1 populations (1680 plants in all), obtained as following [F1(Ler x C24) x Ler], [Ler x F1(Ler x C24)], [F1(Ler x Atmcc1) x Ler] and [Ler x F1(Ler x Atmcc1)], were genotyped by 143 SNPs homogenously distributed on the whole genome with a mean interval length of 800 kb. Genotyping was performed using the patented KASP SNP genotyping system that uses Fluorescent Resonance Energy Transfer (FRET) probes on an arrayed 96 well plate resulting in high throughput and very efficient SNPs detection. Wide analysis revealed that histone acetylation is not determinant for heterochiasmy. Furthermore, genotyping of Atmcc1 evidenced that T-DNA insertion was associated to a reciprocal translocation involving chromosomes 3 and 4. Interestingly, as a consequence of chromosome rearrangements a global redistribution of crossovers along chromosomes occurred.