Plant, Animal & Microbe Genomes X Conference

January 12-16, 2002
Town & Country Convention Center
San Diego, CA

Workshop: Cotton
            

A HIGH-DENSITY GENETIC LINKAGE MAP OF TETRAPLOID COTTON GENOME

¹ Center for Applied Genetic Technologies, University of Georgia, Athens, GA 30602

² Dept. of Soil and Crop Science, Texas A&M University, College Station, TX 77843

³ Botany Department, Iowa State University, Ames, IA 50011

A high-density genetic linkage map of the tetraploid cotton genome has been developed using the segregating data of an F2 population derived from a cross between Gossypium hirsutum race “palmeri” and G. barbadense acc. “K101”. The map included 2662 loci based on 2106 probes, and spanned about 4700 cM, in 26 linkage groups of 58-174 loci and 83.8-316 cM, with an average distance of 1.73 cM between loci. Approximately 70% of the probes are cDNAs, 25% are genomic DNAs and 5% are SSRs. Though individual chromosome showed quite a difference in length, the A and D sub-genomes as a whole had a similar recombination length (2460 cM vs 2240 cM). Comparison of duplicated loci on A and D sub-genomes indicated that 5 pairs of chromosomes have a one-to-one collinear arrangement. Each of the remaining chromosomes showed a collinear relationship with parts of two other chromosomes. Based on the collinear distribution of certain probes, six reciprocal translocations were deduced. There also appeared to be some inversions in the two sub-genomes. Loci on this map are being used as anchor markers to build a physical map of cotton, and to map agronomically important QTLs and qualitative traits such as fiber mutations. Most of the mapped probes have been sequenced and are being applied to the analysis of evolutionary relationships between cotton and other plants.