The road to crossovers: plants have their say

Abstract

Crossovers involve the reciprocal exchange of large fragments of genetic material between homologous chromosomes during meiosis. In this way, crossovers are the basis of genetics. Remarkably, the number and distribution of crossovers on chromosomes are closely controlled. Data from various model organisms (notably Saccharomyces cerevisiae) show that the distribution of crossovers results from a series of tightly regulated events involving the formation and repair of double-strand breaks and interference. Recent advances in genetic and cytological tools, particularly for studying Arabidopsis thaliana, have enabled crossover control in plants to be studied in more detail. In this article, we discuss the contribution of plant studies to meiosis research, particularly to our understanding of crossover control and interference, and we evaluate models of interference.

High-resolution skim genotyping by sequencing reveals the distribution of crossovers and gene conversions in Cicer arietinum and Brassica napus

“…Cells repair DSBs in two ways: either by reciprocal exchange of DNA between homologous chromosome arms (crossovers) or by non-reciprocal exchange of genetic material (non-crossovers). A subset of non-crossovers are gene conversions, where fragments from homologous regions in the partner chromosome are used as a template to connect the two pieces of chromosome, thus fixing the DSB (for a review, see (Mezard et al, 2007)). …”

Repeated Polyploidy Drove Different Levels of Crossover Suppression between Homoeologous Chromosomes inBrassica napusAllohaploids

“…For all these outcomes, the exclusive formation of crossovers (COs) between homologous chromosomes is required (Hamant et al, 2006). Our knowledge of the genes and mechanisms involved in meiotic recombination and CO formation in plants has received a boost in the last 6 years with the use of Arabidopsis thaliana, rice (Oryza sativa), and maize (Zea mays) as model systems (Mezard et al, 2007;Mercier and Grelon, 2008). However, little is known about natural variation in recombination rates within species (Sä ll, 1990;SanchezMoran et al, 2002;Anderson et al, 2003;Esch et al, 2007;Bovill et al, 2008), which is an important issue for understanding how recombination is regulated in the wild.…”

Analysis of Arabidopsis genome-wide variations before and after meiosis and meiotic recombination by resequencing Landsberg erecta and all four products of a single meiosis

“…This allows direct examination of the consequence of meiotic recombination in parallel cultures derived separately from the four spores, using ''tetrad analysis'' (Zickler and Kleckner 1999). Tetrad analysis has contributed significantly to the understanding of the molecular basis of meiotic recombination, including strong support for the steps in the double-strand break repair model (DSBR) (Zickler and Kleckner 1999;Keeney 2001;Ma 2006;Mezard et al 2007) and used in yeast to examine the frequency and genomewide distribution of meiotic recombination (Mancera et al 2008;Qi et al 2009). Here, we combined next-generation sequencing and tetrad analysis to investigate natural variations and meiotic recombination in the flowering plant Arabidopsis.…”