PHYLOGENETIC ANALYSIS OF COTTON SPECIES (DIPLOID GENOMES) USING SINGLE NUCLEOTIDE POLYMORPHISMS (SNPs) MARKERS

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. A(1) and A(2) genomes were most similar (98.0%) while D-9 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.