Yangtze River, an insignificant genetic boundary in tufted deer (Elaphodus cephalophus): the evidence from a first population genetics study.

Zhonglou Sun,Hui Wang,Mujia Pang,Baowei Zhang,Tao Pan

doi:10.7717/peerj.2654

Abstract

Great rivers were generally looked at as the geographical barrier to gene flow for many taxonomic groups. The Yangtze River is the third largest river in the world, and flows across South China and into the East China Sea. Up until now, few studies have been carried out to evaluate its effect as a geographical barrier. In this study, we attempted to determine the barrier effect of the Yangtze River on the tufted deer (Elaphodus cephalophus) using the molecular ecology approach. Using mitochondrial DNA control region (CR) sequences and 13 nuclear microsatellite loci, we explored the genetic structure and gene flow in two adjacent tufted deer populations (Dabashan and Wulingshan populations), which are separated by the Yangtze River. Results indicated that there are high genetic diversity levels in the two populations, but no distinguishable haplotype group or potential genetic cluster was detected which corresponded to specific geographical population. At the same time, high gene flow was observed between Wulingshan and Dabashan populations. The tufted deer populations experienced population decrease from 0.3 to 0.09 Ma BP, then followed by a distinct population increase. A strong signal of recent population decline (T = 4,396 years) was detected in the Wulingshan population by a Markov-Switching Vector Autoregressions(MSVAR) process population demography analysis. The results indicated that the Yangtze River may not act as an effective barrier to gene flow in the tufted deer. Finally, we surmised that the population demography of the tufted deer was likely affected by Pleistocene climate fluctuations and ancient human activities.

Highlights

Natural landscape features, such as rivers, can function as genetic boundaries and shape the population structure of animals because they can act as an important geographical barrier to dispersal and gene flow (Funk et al, 2001; Whiteley, Spruell & Allendorf, 2004; Coulon et al, 2004; Hartl et al, 2005; Coulon et al, 2006; Wang et al, 2015)
The level of genetic diversity was estimated by 13 nuclear microsatellite loci (Table 2)
The mean HE (HE = 0.823) and average HO (HO = 0.781) showed high genetic diversity in 13 nuclear microsatellite loci (Table 2). These results indicated that these deer populations may still possess high genetic diversity, despite serious population decline

Summary

Introduction

Natural landscape features, such as rivers, can function as genetic boundaries and shape the population structure of animals because they can act as an important geographical barrier to dispersal and gene flow (Funk et al, 2001; Whiteley, Spruell & Allendorf, 2004; Coulon et al, 2004; Hartl et al, 2005; Coulon et al, 2006; Wang et al, 2015). Even for some large mammals, such as the grey wolf, Canis lupus (Carmichael et al, 2001), the giant panda, Ailuropoda melanoleuca (Zhu et al, 2011), and the white-tailed deer, Odocoileus virginianus (Robinson et al, 2012), rivers still presented substantial limits to dispersal and gene flow in spite of their high mobility. Rivers may facilitate gene flow in some amphibians (Spear et al, 2005)

Methods

Results

Conclusion