Molecular mapping of the gene dense spike (dsp.ar) to the centromeric region of barley chromosome 7H using Micro-Synteny and comparative genomics

genome studies of different plant until 1998 revealed that about 50% of the newly identified genes, show sequence homology and conserved genomic order in compare with those have been known in the past. This became the concept for emergence of comparative genomics. Using micro-synteny and molecular colinearity among barley un-sequenced and some sequenced genomes belonging to tribe Poaceae (Gramineae) including rice, maize and Brachypodium, the chromosomal location of the gene dense spike (dsp.ar) was investigated. The gene dsp.ar is one of the developmentally genes in barley associated with spike morphology and grain yield, which is economically very important. A 3:1 segregation ratio was observed for the dense spike phenotype among F2 plants obtained from the cross Bowman x BW265, indicating that a single gene is responsible for the phenotype. Saturation of centromeric region of barley chromosome 7H was accomplished by developing STS, EST and SNP markers and converting those to PCR-based markers by either CAPS or Pyrosequencing. Among 1993 progenies of this population, 39 lines showed recombination for polymorphic markers. The link flanking markers CAPSK06413 and SC57808 for dsp.ar gene with less than 1cM distance can be utilized for marker assisted breeding (MAS) and map-based cloning of this gene in further studies. The methods used here can be generalized to define strategies for other plant genes and genomes and utilized in plant molecular breeding projects as well. Here describe in details will be discussed.