Chromosomal rearrangements differentiating the ryegrass genome from the Triticeae, oat, and rice genomes using common heterologous RFLP probes.

An restriction fragment length polymorphism (RFLP)-based genetic map of ryegrass (Lolium) was constructed for comparative mapping with other Poaceae species using heterologous anchor probes. The genetic map contained 120 RFLP markers from cDNA clones of barley (Hordeum vulgare L.), oat (Avena sativa L.), and rice (Oryza sativa L.), covering 664 cM on seven linkage groups (LGs). The genome comparisons of ryegrass relative to the Triticeae, oat, and rice extended the syntenic relationships among the species. Seven ryegrass linkage groups were represented by 10 syntenic segments of Triticeae chromosomes, 12 syntenic segments of oat chromosomes, or 16 syntenic segments of rice chromosomes, suggesting that the ryegrass genome has a high degree of genome conservation relative to the Triticeae, oat, and rice. Furthermore, we found ten large-scale chromosomal rearrangements that characterize the ryegrass genome. In detail, a chromosomal rearrangement was observed on ryegrass LG4 relative to the Triticeae, four rearrangements on ryegrass LGs2, 4, 5, and 6 relative to oat, and five rearrangements on ryegrass LGs1, 2, 4, 5, and 7 relative to rice. Of these, seven chromosomal rearrangements are reported for the first time in this study. The extended comparative relationships reported in this study facilitate the transfer of genetic knowledge from well-studied major cereal crops to ryegrass.

Sim S ，Chang T ，Curley J ，Warnke SE ，Barker RE ，Jung G ... -  《THEORETICAL AND APPLIED GENETICS》

An enhanced molecular marker based genetic map of perennial ryegrass (Lolium perenne) reveals comparative relationships with other Poaceae genomes.

A molecular-marker linkage map has been constructed for perennial ryegrass (Lolium perenne L.) using a one-way pseudo-testcross population based on the mating of a multiple heterozygous individual with a doubled haploid genotype. RFLP, AFLP, isoenzyme, and EST data from four collaborating laboratories within the International Lolium Genome Initiative were combined to produce an integrated genetic map containing 240 loci covering 811 cM on seven linkage groups. The map contained 124 codominant markers, of which 109 were heterologous anchor RFLP probes from wheat, barley, oat, and rice, allowing comparative relationships between perennial ryegrass and other Poaceae species to be inferred. The genetic maps of perennial ryegrass and the Triticeae cereals are highly conserved in terms of synteny and colinearity. This observation was supported by the general agreement of the syntenic relationships between perennial ryegrass, oat, and rice and those between the Triticeae and these species. A lower level of synteny and colinearity was observed between perennial ryegrass and oat compared with the Triticeae, despite the closer taxonomic affinity between these species. It is proposed that the linkage groups of perennial ryegrass be numbered in accordance with these syntenic relationships, to correspond to the homoeologous groups of the Triticeae cereals.

Jones ES ，Mahoney NL ，Hayward MD ，Armstead IP ，Jones JG ，Humphreys MO ，King IP ，Kishida T ，Yamada T ，Balfourier F ，Charmet G ，Forster JW ... -  《GENOME》

Comparative mapping in grasses. Oat relationships.

Van Deynze AE ，Nelson JC ，O'Donoughue LS ，Ahn SN ，Siripoonwiwat W ，Harrington SE ，Yglesias ES ，Braga DP ，McCouch SR ，Sorrells ME ... -  《molecular and general genetics》

Saturated molecular map of the rice genome based on an interspecific backcross population.

Causse MA ，Fulton TM ，Cho YG ，Ahn SN ，Chunwongse J ，Wu K ，Xiao J ，Yu Z ，Ronald PC ，Harrington SE ... -  《GENETICS》

Comparative mapping in grasses. Wheat relationships.

Van Deynze AE ，Nelson JC ，Yglesias ES ，Harrington SE ，Braga DP ，McCouch SR ，Sorrells ME ... -  《molecular and general genetics》