POPULATION-BASED RECOMBINATION MAPS ESTIMATED WITH TWO DIVERGING EUROPEAN AND ASIAN POPULATIONS ON BREAD WHEAT CHROMOSOME 3B Abstract uri icon

abstract

  • During meiosis, crossovers create new allele associations by reciprocal exchange of DNA between homologous chromosomes. This recombination phenomenon is widely exploited in breeding programs to combine favorable alleles in a new variety. Recombination maps of cultivated plant species are generally estimated from bi-parental populations. An alternative method consists in inferring recombination maps based on linkage disequilibrium patterns using a population of unrelated individuals, leading to higher resolution maps. In this study, population-based recombination maps of chromosome 3B of bread wheat (Triticum aestivum L.)were built for two diverging populations (European and Asian) of 200landraces genotyped with respectively 11420 and 12023 polymorph SNP on 3B chromosome, using PHASE Markov Chain Monte Carlo model in sliding windows of 5Mb and steps of 1Mb. The recombination maps obtained from the European or Asian populations and the Chinese Spring x Renan bi-parental populations showed a consistent structure, with an increasing recombination rate from centromere to telomeres. Intense recombination hotspots in the populations were defined as intervals with recombination rate superior to 10 times the background recombination rate in the window. They were defined as the top 10 % recombinant intervals in the bi-parental population. The density of recombination hotspots increased as well from centromere to telomeres. We observed 113 and 105 intense hotspots in the European and the Asian recombination maps respectively, and 47 in the bi-parental recombination map. Around 40% of intense hotspots were conserved between European and Asian populations. Although most (83%)of bi-parental hotspots were consistent with European and/or Asian populations. Only 15% of Asian and European intense hotspots were shared with the bi-parental map.

publication date

  • July 2019