Molecular genetic, cell biological and genomic analyses of meiotic recombination in Arabidopsis
Hong Ma

State Key Laboratory of Genetic Engineering, Institute of Plant Biology, Center for Evolutionary Biology, School of Life Sciences, Fudan University, Shanghai 2000433, China; Department of Biology, the Pennsylvania State University, University Park, PA 16802 USA.

Abstract
Meiotic recombination is crucial for normal meiotic homolog association and segregation, thereby ensuring normal fertility in plants and other eukaryotes. In addition, meiotic recombination redistributes genome variations and affects allelic frequencies each generation. We have identified and characterized several Arabidopsis genes important for meiotic recombination using molecular genetics. To identify additional genes potentially important for meiotic recombination and other meiotic functions, we analyzed Arabidopsis male meiocyte transcriptome using high throughput sequencing of cDNAs and detected the expression of ~16,000 genes. We found that, among 3,378 known Arabidopsis gene families, 3,265 contained meiocyte-expressed genes and 18 were overrepresented in male meiocytes. In addition, a large number of genes expressed in meiocytes are conserved in other organisms, including 503 single-copy genes shared between Arabidopsis, mouse and yeast. Among the genes detected in Arabidopsis meiocytes are those similar to genes for recombination or DNA synthesis, suggesting that they might be involved in meiotic recombination; genetic and cell biological studies of some of these genes reveal new mechanisms of meiotic recombination and support a key role for lagging strand DNA synthesis in crossover formation via the interference-sensitive pathway. The highly conserved nature of these genes further suggests that the newly uncovered mechanisms might be widespread in eukaryotes.