K-means clustering and STRUCTURE analyses of genetic diversity in Tamarix L. accessions

Authors: HABIBOLLAH IJBARI, MASOUD SHEIDAI, AHMAD-REZA MEHRABIAN, ZAHRA NOORMOHAMMADI, SOMAYEH GHASEMZADEH-BARAKI

Abstract: Tamarix L. accessions were collected from Sistan and Baluchestan Province of Iran, covering an area of about 60 km located in the southeast of Iran. The present investigation was performed to study the genetic structure of Tamarix populations in this province and present some information about gene flow among these populations. Forty-two tree specimens were randomly collected and studied for molecular and morphological diversity. Based on morphological descriptions we recognized 3 species that were confirmed by detailed morphometric and genetic analysis. The studied tree specimens were separated in 3 distinct clusters by UPGMA clustering and principal coordinate analysis and multidimensional scaling ordination methods. Clustering of molecular (ISSR) data showed some degree of genetic variation within each species. Similarly, STRUCTURE analysis and K-means clustering revealed some degree of genetic admixture among the studied accessions. NeighborNet and reticulograms revealed some degree of gene exchange among the studied populations. AMOVA and the Hickory test showed significant genetic differences of the studied populations and the Mantel test showed significant correlation between genetic distance and geographical distance of these populations.

Keywords: Genetic variation, species relationship, Tamarix

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