Submitted to: Journal of Heredity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/20/1999
Publication Date: 11/1/2000
Citation: ZHANG, X.Q., ROSS, K., GUSTAFSON, J.P. PHYSICAL LOCATION OF HOMOEOLOGOUS GROUPS 5 AND 6 MOLECULAR MARKERS MAPPED IN TRITICUM AESTIVUM L. JOURNAL OF HEREDITY. 2000. V. 91(6). P. 441-445. Interpretive Summary: There has long been a problem with establishing the physical location of genes on regions of chromosomes and establishing whether or not there are clusters and gaps of genes located along chromosomes. The knowledge of the physical location of genes can potentially make the future gene manipulation and cloning of the genes significantly easier. A study was designed to establish the physical location of molecular markers and genes on chromosomes of wheat. The results of the study indicated that markers/genes present in wheat are not distributed randomly along the chromosomes, but can be bunched together in clusters. Therefore, many wheat chromosomes consist of clusters of markers and genes, and large gaps where there are no presently known genes or markers. The results of this study have important implications for breeders and geneticists who are trying to manipulate genes in wheat and possibly for molecular biologists who are trying to transform wheat. The impact of this research is that it appears that there may be regions of wheat chromosomes that are susceptible to gene manipulation and others that appear not useable for genetic manipulation.
Technical Abstract: In situ hybridization was used to map21 restriction fragment length polymorphism (RFLP) probes to linkage groups 5 and 6 of hexaploid wheat (Triticum aestivum L. em Thell.). By this means, physical distances and genetic distances between adjacent markers could be compared. All 21 probes hybridized to the corresponding chromosomes. The linear order and linkage relationships among the DNA probes on the in situ-based physical maps were the same or nearly the same as those on the RFLP-based genetic maps. Significant differences existed between the genetic and physical distances of the probes, consistent with the indication of "hot" and "cold" spots of recombination distributed along the chromosomes. Both genetic and chromosomal maps showed non-homoeologous rearrangement in the terminal regions of chromosome arms 5AL and 6BS.