The effects of sex ratio in estimation of genetic differentiation in Populus nigra populations


Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Edebiyat Fakültesi, Biyolojik Bilimler Bölümü, Türkiye

Tezin Onay Tarihi: 2017

Öğrenci: BURAK YELMEN

Danışman: ZEKİ KAYA

Özet:

Effective population size is an important concept in conservation biology. Biased sex ratio lowers effective population size, consequently causing loss of genetic variation. In this study, available microsatellite DNA marker data of 121 Populus nigra clones originated from 5 geographical regions were analyzed to evaluate genetic diversity of genders and to investigate possible effects of sex ratio on differentiation in these populations in Turkey. There was an abundance of identical genotypes in the dataset. The same genotypes were observed both in males and females that might be suggesting a rare occurrence of deviation from dioecism. Three clusters were estimated in structure analysis with k-means clustering. Significant differentiation was found among clusters. However, they did not correlate with geographical assignment of clones. Also, there was no variation between pre-determined five geographical populations. Overall allelic richness was found to be similar for both genders whereas heterozygosity was higher in males. Both male and female group had private alleles on all studied loci. Although there was no significant variation between genders, combination of four loci showed a slight empirical differentiation. Additionally, a simulation software prototype was developed to see effects of sex ratio on diversity and differentiation in future generations given the available molecular data. Results showed that if biased sex ratio persists, allele loss and fixation might occur in a higher rate, causing a loss of variation and faster differentiation in case of isolation.