Introgression Genomics's in the Grasses.

Introgression maps have been developed for each of the 7 linkage groups of Lolium/Festuca. These introgression maps have been used to determine the physical and genetic location of SNPs derived from the coding sequence from approximately 1000 BACs from the rice genome. Many of the SNPs developed are from rice sequences previously used to generate primers that have been genetically mapped in barley. Cross species markers developed at the John Innes Centre, Norwich, UK, have also been introgression mapped. The sequences used to develop the SNPs have also been aligned with the newly developed Brachypodium physical map.

Thus this work is providing a genome wide comparative analysis of gene order and distribution in Lolium, rice, Brachypodium, wheat and barley. It will also allow grass to “talk to” the other monocot species providing the mechanism for the amalgamation of data on the genetic control of target traits across the monocots.

The introgression maps and primers developed during this project also provide the basis for the initial alignment of the Lolium perenne physical map to established chromosome-based introgression and genetic maps. Contigs developed during the physical mapping will be aligned to the bins on the introgression maps using common markers.

We have also demonstrated that a substantial component of the coding sequences in monocots is localised proximally in regions of very low recombination frequencies. The implication of these findings is that during domestication of monocot plants, selection has concentrated on genes located in the terminal regions of chromosomes within areas of high recombination frequency. Thus a large proportion of the genetic variation available for selection of superior plant genotypes has not been exploited.

Introgression maps have been developed for each of the 7 linkage groups of Lolium/Festuca. These introgression maps have been used to determine the physical and genetic location of SNPs derived from the coding sequence from approximately 1000 BACs from the rice genome. Many of the SNPs developed are from rice sequences previously used to generate primers that have been genetically mapped in barley. Cross species markers developed at the John Innes Centre, Norwich, UK, have also been introgression mapped. The sequences used to develop the SNPs have also been aligned with the newly developed Brachypodium physical map.

Thus this work is providing a genome wide comparative analysis of gene order and distribution in Lolium, rice, Brachypodium, wheat and barley. It will also allow grass to “talk to” the other monocot species providing the mechanism for the amalgamation of data on the genetic control of target traits across the monocots.

The introgression maps and primers developed during this project also provide the basis for the initial alignment of the Lolium perenne physical map to established chromosome-based introgression and genetic maps. Contigs developed during the physical mapping will be aligned to the bins on the introgression maps using common markers.

We have also demonstrated that a substantial component of the coding sequences in monocots is localised proximally in regions of very low recombination frequencies. The implication of these findings is that during domestication of monocot plants, selection has concentrated on genes located in the terminal regions of chromosomes within areas of high recombination frequency. Thus a large proportion of the genetic variation available for selection of superior plant genotypes has not been exploited.