Analysis of targeted base ITS sequences in the genus Astragalus using Hill Climbing Algorithm

The genus Astragalus is an important taxon with recognized center/centers of diversification and originationin Iran. different species of the genus relating to old and new world occurs in Iran. So, this region has beenof great attentions considering phylogenetic studies of the genus. In the present study ۳۰ accessions ofdifferent species of the genus were sequenced targeting ITS۱ region and ۳۲ seqneced datasets were addedfrom NCBI data base, making a complete representative of ۱۰ phylogenetically close sections of the genusin Iran. Forward and reverse contigs were alighned and used for further analysis. The Hill Climbing algorithmwas chosen as the best model representing phylogenetic relationships, testing by GTR+I+G method and,selected through AKAIKE INFORMATION CRITERTION test, by the generation of ۲,۰۰۰,۰۰۰ generations.The validity of the number of generations was checked with Tracer software. The resulting standard deviationwas estimated to be ۰.۰۲۲. The outgrouping taxa were defined and the resulting tree was plotted using FigTreesoftware. The Consistency Index (CI) was calculated for the tree as; CI= ۰.۳۹۱. The results indicated thatdifferent species were grouped based on their similarity and dissimilarity and grouped mainly based on theirevolutionary priorities defining two specific clades relating to old and new world respectively. Among them۵ species A. aegobromus, A. coluteocarpus, A. siliquosus, A. zerdanus and A. hamosus, all belonging to theold world, were grouped apart. The rest of the species belonging to ۲ sections of Hymenostegis andAnthylloidei were grouped in a specific clade, being a representative of the new world taxa occurring in Iran.The results indicated that although the genus Astragalus has been experiencing different geographical andecological conditions in Iran, the species occurring in Iran follow thier ancestral relationships and possess apotential germplasm to be used with conservation porposus.

Keywords:

Fabaceae , Phylogeny , Bayasian method , ITS , Iran