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Genus cotton has total 50 species, diploid species fall into 8 genomic groups (A-G, and K). To the extent of our knowledge, frequency of single nucleotide polymorphisms (SNPs) has not been calculated in genes of multiple genomes of the genus Gossypium. Here we present the frequency of SNPs in the transcribed regions of the multiple genes, and their utility in resolving phylogenies among 11 diploid species representing five of the eight diploid genomes of the genus Gossypium. We explored the expressed sequence tags (ESTs) data set of G. arboreum showing homology with genes encoding for mitochondrial small heat shock protein (MT-sHSP), histone H2B1, S-adenosyl methionine synthetase, cytochrome p450, actin-depolymerizing factor 2, C-terminal domain of helicases and histone H2B3 for designing primers. The resultant PCR products amplifying partial gene sequences were sequenced. In total, 61 SNPs were detected in cotton genomes which include 53 substitutions and 8 Indels in the total 1920 bp genome length. Phylogenetic analysis using this data revealed grouping of genomes comparable with previous studies. A1 and A2 genomes were most similar (98.0%) while D9 and Oryza genomes were least similar (31.2%). Oryza was most distantly related with other genomes. In conclusion SNPs are potent markers to delineate cotton genomes according to their evolutionary positions. [ABSTRACT FROM AUTHOR]

Microsatellite regions in DNA fragments of Gossypium arboreum were explored and PCR products 500-800 bp long were analyzed for genomic simple sequence repeats (gSSRs). From 39 segments, 23 short gSSRs were identified; on average they occurred every 1.6 kb. Primers were used to amplify fragments from 18 diploid species representing 6 diploid genomes and 1 tetraploid species, G. hirsutum (AD). The phylogeny of diploid genomes was subsequently determined. No primer amplified the DNA from all genotypes; however, amplification occurred in 59% of 437 PCR events. All genomes were grouped into 2 clusters (a and b). The obtained phylogeny of the species parallels previous reports. The strategy adopted here is an efficient method of identifying new gSSRs from species not extensively explored. [ABSTRACT FROM AUTHOR]