Chromosome structural changes in diploid and tetraploid A genomes of Gossypium.
The genus Gossypium, which comprises a divergent group of diploid species and several recently formed allotetraploids, offers an excellent opportunity to study polyploid genome evolution. In this study, chromosome structural variation among the A, At, and D genomes of Gossypium was evaluated by comparative genetic linkage mapping. We constructed a fully resolved RFLP linkage map for the diploid A genome consisting of 275 loci using an F2 interspecific Gossypium arboreum x Gossypium herbaceum family. The 13 chromosomes of the A genome are represented by 12 large linkage groups in our map, reflecting an expected interchromosomal translocation between G. arboreum and G. herbaceum. The A-genome chromosomes are largely collinear with the D genomes, save for a few small inversions. Although the 2 diploid mapping parents represent the closest living relatives of the allotetraploid At-genome progenitor, 2 translocations and 7 inversions were observed between the A and At genomes. The recombination rates are similar between the 2 diploid genomes; however, the At genome shows a 93% increase in recombination relative to its diploid progenitors. Elevated recombination in the Dt genome was reported previously. These data on the At genome thus indicate that elevated recombination was a general property of allotetraploidy in cotton.
Desai
Aparna
A
Coastal Plains Experiement Station, University of Georgia, Tifton, 31793, USA.
Chee
Peng W
PW
Rong
Junkang
J
May
O Lloyd
OL
Paterson
Andrew H
AH
D007446:Chromosome Inversion; D002874:Chromosome Mapping / Q000379:methods; D020090:Chromosome Segregation; D032461:Chromosomes, Plant / Q000378:metabolism*; D018628:Gene Dosage; D020131:Genes, Duplicate; D008040:Genetic Linkage; D005819:Genetic Markers; D018745:Genome, Plant; D003368:Gossypium / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D026801:Synteny; D014178:Translocation, Genetic
D005819:Genetic Markers