|Holland, Jim - Jim|
Submitted to: Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/19/2000
Publication Date: N/A
Interpretive Summary: Genome maps are useful for plant breeding, genetic diversity analyses, and gene mapping in crop species. Comprehensive genome maps are lacking for cultivated oat, which has a very large genome. Previous oat genome maps have used wild oat species that have a different base number of chromosomes than cultivated oat, or they have lacked complete coverage of the cultivated oat genome. We developed a new oat mapping population that has advantages over previous mapping populations in that it is a larger sample size of cultivated oat than has been previously mapped. Furthermore, we primarily used genetic markers that have been mapped in other grass crop species, such as wheat, barley, rice, and maize, as well as in both previous wild and cultivated oat genome maps. This allowed us to construct the best available map of the cultivated oat genome, although we still have not completely mapped the entire oat genome. We were able to analyze the pattern of duplicated genes in the genome and the conserved arrangement of genes in our map and other oat maps. We found that the oat genome is very complex, with many genes being duplicated on multiple chromosomes, and that the oat genome consists of chromosomes that once existed in triplicate copies that have since been rearranged considerably. We can use our map to compare the structure of the oat genome to that of other grass crops.
Technical Abstract: A cultivated oat linkage map was developed using a recombinant inbred population of 136 F6:7 lines from the cross Ogle TAM O-301. A total of 441 marker loci, including 355 RFLP, 40 AFLP, 22 RAPD, five STS, one SSR, 12 isozyme loci, and four discrete morphological traits, was mapped. Fifteen loci remained unlinked, and 426 loci produced 34 linkage groups (with two to 43 loci each) spanning 2049 cM of the oat genome (from 4.2 - 174.0 cM per group). Comparisons to other Avena maps revealed 35 genome regions syntenic between hexaploid maps and 16 to 34 regions conserved between diploid and hexaploid maps. Those portions of hexaploid oat maps that could be compared were completely conserved. Considerable conservation of diploid genome regions on the hexaploid map also was observed (89 - 95%); however, at the whole-chromosome level, colinearity was much lower. Comparisons among linkage groups, both within and among Avena mapping populations, revealed several putative homoeologous linkage group sets as well as some linkage groups composed of segments from different homoeologous groups. The relationships between many Avena linkage groups remain uncertain, however, due to incomplete coverage by comparative markers and to complications introduced by genomic duplications and rearrangements.