Proceedings of the XLV Italian Society of Agricultural Genetics - SIGA Annual Congress

Salsomaggiore Terme, Italy - 26/29 September, 2001

ISBN 88-900622-1-5

Oral Communication Abstract

MOLECULAR MARKERS AND THE SPACE AROUND GENES

OSBORN T. C.

University of Wisconsin, 1575 Linden Dr., Madison, WI 53506, USA

tcosborn@facstaff.wisc.edu

Molecular markers tightly linked to target loci are useful for cloning and manipulating genes of interest, but markers in the space around genes of interest also can provide key genomic tools. One use for these markers is to identify and zero in on candidate genes by comparative mapping to well-studied model organisms. Brassica crop species are closely related to Arabidopsis and they vary widely in flowering time, a well-studied trait in Arabidopsis. A triplicated region of the basic Brassica genome contains several flowering time QTLs and is homologous to a region of chromosome 5 in Arabidopsis where flowering time genes have been isolated. Results from comparative fine mapping in Brassica using cloned Arabidopsis flowering time genes indicate that a major flowering time QTL in this region corresponds to FLC, a key regulator of flowering time in Arabidopsis. Markers in the space around FLC homologs are being used to define the effects of allleles at multiple FLC loci in several Brassica genotypes, providing insight on the function of replicated loci in polyploids. Another use for markers in the space around genes is to eliminate regions around elite alleles during introgression or selection in segregating progenies. This not only avoids undesirable linked genes, but it also can prevent the accumulation dead genome space in germ plasm containing elite alleles. As the number of elite alleles required in cultivars increases, the effective management of space around genes will become increasingly important.