FISH Study Of Gossypium Mustelinum, Gossypium Darwinii And Isolation Of Centromere FISH Probe Of Gossypium D Genome

It has been proposed previously that extant A- and D-genome species are most closely related to the diploid progenitors of the tetraploid(AD genome),Yet few data address the question of the actual diploid ancestor of tetraploid D-subgenome, the relationship between the diploid genome and tetraploid genome, and some diploids'homologous relationship, et al. Most investigation of the original and evolution of tetraploid cotton are focus on G. hirstum and G. barbadense, the research of G. mustelinum and G. darwinii is very few. So, FISH research of G. mustelinum and G. darwinii is very important for the original and evolution of tetraploid cotton.This research carries on the fluorescence in situ hybridization analysis of Gossypium mustelinum and Gossypium darwinii. The contents include the diploid ancestors of Gossypium mustelinum and Gossypium darwinii, rDNA concerted evolution, the relationship between diploid genome and tetraploid genome, and Identified centromere marker of cotton. The main results are as follows:A pair of median satellites located at two pair chromosomes of G. mustelinum, this is not found in other species of cotton. FISH show three 45S rDNA loci at chromosomes 2, 4, 9 of G. mustelinum, one of them is very bid and the shape is similar to the short arm, the other two was minor loci, all loci is located at A-Subgenome, this indicate that the evolution mechanism of 45S rDNA in G. mustelinum maybe different with other tetraploid cotton. FISH show two major and one medium 45S rDNA loci at chromosomes 3, 13, 18 of G. darwinii, three minor 45S rDNA loci was detected at chromosomes6, 10, 14.GISH-NOR were detected with G. herbaceum var. africanum but not with G. herbaceum hongxincaomian and G.arboreum shixiya1 as probe, 45S rDNA IGS of G. herbaceum var.africanum maybe similar with diploid D Genome, G. herbaceum var. africanum is the the diplod progenitor of D subgenome of G. darwinii and G. mustelinum. GISH-NOR were detected with diploid D Genome species gDNA as probe, 45S rDNA IGS of all tetraploid cotton are similar with diploid D Genome; karyotype analysis show that the shortest two chromosomes of A-Subgenome is shorter than the longest chromosomes of D-Subgenome; G. thurberi is the diplod progenitor of D subgenome of the G. mustelinum, G. davisonii is the the diplod progenitor of D subgenome of G. darwinii, this means that teroploid cotton is polyphyletic.Signals with B Genome G. anomalum and diplid F Genome G. longicalyx as probe are similar with that of G. herbaceum var. africanum, this means the repetitive sequence of G. anomalum and diplid F Genome G. longicalyx is similar with diploid A Genome while 45S rDNA is similar with diploid D Genome. Signals with E Genome G. somalense as probe are similar with that of G.herbaceum hongxincaomian and G.arboreum shixiya 1, this means the repetitive sequence and 45S rDNA of G. somalense is similar with diploid A Genome cultivatier.Previously study show that G. gossypiodies contain both diploid A,D Genome repetitive sequences, and 45S rDNA of G. gossypiodies is similar with diploid A Genome. In this experiment, All chromosomes of G. mustelinum and G. darwinii was stained red with G. gossypiodies as probe,this indicated that G. gossypiodies contain both diploid A,D Genome repetitive sequences, which are in good agreement with previous results. GISH-NOR were detected at G. mustelinum and G. darwinii, this mean that 45S rDNA of G. gossypiodies is similar with diploid D Genome. Which is opposite with previous results. Fish show C genome G. sturtianum and G Genome G. bickii also contain both diploid A,D Genome repetitive sequences, while 45S rDNA of G. sturtianum is similar with diploid D Genome, and 45S rDNA of G. bickii is similar with diploid A GenomeBAC clone 150D24 derived SSR marker BNL3563 which from linkage map Chromosome 10 (A-subgenome) was identified in this program. FISH show BAC clone 150D24 was located at centromere region of diploid D Genome and D subgenome and two chromosomes of A subgenome of teraploid cotton, but not in diploid A,C,E Genome cotton. Sequence date of subclone show BAC clone 150D24 contain repetitive sequence retrotransposon.