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ARS Home » Midwest Area » St. Paul, Minnesota » Plant Science Research » Research » Publications at this Location » Publication #74162
Title: THE DIFFICULT TASK OF ASSIGNING HOMOEOLOGOUS CHROMOSOME GROUPINGS IN OAT (AVENA SATIVA L., 2N = 6X = 42) AS REVEALED BY ANEUPLOIDS AND MOLECULAR MARKERS

Author
item KIANIAN, SHAHRYAR - UNIVERSITY OF MINNESOTA
item WU, BAI-CHAI - UNIVERSITY OF MINNESOTA
item FOX, STEPHEN - UNIVERSITY OF MINNESOTA
item Rines, Howard
item PHILLIPS, RONALD - UNIVERSITY OF MINNESOTA

Submitted to: Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/18/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: The organization of the genetic material in oat and bread wheat is more complex than in other cereals such as corn, rice, and barley. Common oats and bread wheat evolved several thousands of years ago with each derived from the combining of three ancestral species. Recognition and detailed characterization of a conserved triplicate nature in the genetic components in wheat has allowed geneticists and breeders to effectively manipulate gene transfers among wheat varieties as well as to introduce genes from related wheat species to improve the productivity and quality of bread wheat. However, in oat much less has been known about the detailed organization of the three contributed genetic components. Through the use of modern DNA analysis techniques we have analyzed a series of especially developed oat lines that are missing various chromosomes (the physical components of the genetic material in a cell). By correlating the absence of various tested DNA sequences with the absence of various chromosomes, w have learned that the genetic material of oat is organized mainly as triplicated chromosome segments rather than as intact chromosome sets as is wheat. This increased understanding of how the oat genetic material is organized will enable the development of more effective strategies for genetic and breeding manipulations to improve disease resistance and nutritional quality of oat.

Technical Abstract: Nullisomic lines of hexaploid oat A. sativa cv. Sun II were used to assign 134 DNA sequences to ten chromosome associated syntenic groups. A limited set of ditelosomic lines allowed localization of subsets of these sequences to six chromosome arms. An advantage of using such aneuploids in mapping is in the assignment of gene families, monomorphic RFLP sequences, and oat linkage groups to chromosomes. The published hexaploid oat RFLP linkage map has several more linkage groups than expected based on chromosome number. Using nullisomics, nine linkage groups were assigned to six physical chromosomes; using ditelosomics three of these linkage groups were assigned to their respective chromosome arms. Among the ten syntenic groups identified here, two pairs of two chromosomes each share 28 to 29% sequence homoeology and are believed to represent segmental homoeologous groups. Genome assignment based on C-banding, ancestral genome affinity based on sequence similarity to diploid oat, and nullisomic-tetrasomic compensation are some of the additional criteria used in determining homoeologous relationships. However, chromosomal rearrangements such as translocations and inversions make such determinations difficult. Due to these and other evolutionary forces, segmental homoeology instead of whole chromosome homoeology appears to best describe the genome organization in hexaploid oat.