Development and Utilization of Microsatellite Markers to Assess Genetic Variation Coupled with Modelling Range Shifts of Dodonaea Viscosa in Isolated Taita Hills and Mount Kenya Forests

Abstract

For the protection and maintenance of fragmented and highly disturbed habitats, understanding genetic variation is essential. The Taita Hills of Kenya is the northernmost part of the Eastern Arc Mountains and has been identified as one of the top 10 biodiversity hotspots globally. The current forests in the Taita Hills have been highly fragmented over the past century. In order to appraise the influence of anthropological disturbance and fragmentation on the genetic variation of Dodonaea viscosa (Sapindaceae), we studied its preliminary genetic variability and population structure using newly developed microsatellite (SSR) markers, combined with ecological niche modeling analyses. We utilized the Illumina paired-end technology to sequence the D. viscosa’s genome and developed its microsatellite markers. In total, 646,428 sequences were analyzed and 49,836 SSRs were identified from 42,638 sequences. A total of 18 primer pairs were designed to test polymorphism among 92 individuals across eight populations. The average observed heterozygosity and expected heterozygosity ranged from 0.119 to 0.982 and from 0.227 to 0.691, respectively. Analysis of molecular variance (AMOVA) revealed 78% variance within individuals and only 20% among the eight populations. According to SDM results, D. viscosa’s suitable habitats have been gradually reducing since the last glacial maximum (LGM), and the situation will worsen under the extreme pessimist scenario of RCP 8.5. Moreover, genetic diversity was significantly greater in larger fragments. Therefore, urgent conservation management of smaller fragmented patches is necessary to protect this disturbed region and maintain the genetic resources.