Effects of the Tanaka Line on the genetic structure of Bombax ceiba (Malvaceae) in dry‐hot valley areas of southwest China

Abstract

Southwest China is an important biodiversity hotspot. The interactions among the complex topography, climate change, and ecological factors in the dry‐hot valley areas in southwest China may have profoundly affected the genetic structure of plant species in this region. In this study, we determined the effects of the Tanaka Line on genetic variation in the wild Bombax ceiba tree in southwest China. We sampled 224 individuals from 17 populations throughout the dry‐hot valley regions. Six polymorphic expressed sequence tag–simple sequence repeat primers were employed to sequence the PCR products using the first‐generation Sanger technique. The analysis based on population genetics suggested that B. ceiba exhibited a high level of gene diversity (H E: 0.2377–0.4775; I: 0.3997–0.7848). The 17 populations were divided into two groups by cluster analysis, which corresponded to geographic characters on each side of the Tanaka Line. In addition, a Mantel test indicated that the phylogeographic structure among the populations could be fitted to the isolation‐by‐distance model (r 2 = .2553, p < .001). A barrier test indicated that there were obstacles among populations and between the two groups due to complex terrain isolation and geographic heterogeneity. We inferred that the Tanaka Line might have promoted the intraspecific phylogeographic subdivision and divergence of B. ceiba. These results provide new insights into the effects of the Tanaka Line on genetic isolation and population differentiation of plant species in southwest China.

Determinants of Genetic Structure in a Highly Heterogeneous Landscape in Southwest China

“…Moreover, a far higher proportion (78%) of the observed genetic variation could be explained by the joint effect of climatic, topographic, and anthropogenic factors ( Figure 6 ). This finding confirms the importance of these factors in determining the patterns of genetic structure in southwest China (e.g., Ju et al, 2018 ; Yang et al, 2019 ). Although our data show that topography is the main determinant of genetic structure in the LRGR, this relationship can be better understood in the context of climatic factors (e.g., Mosca et al, 2014 ; Li et al, 2019 ).…”

Spatial Distribution of Pollinating Butterflies in Yunnan Province, Southwest China with Resource Conservation Implications

“…The geographic position of West or East Yunnan cannot be applied as a simple criterion for species richness. Similar results were also identified by other studies on species assemblage and diversity, which agreed with our results [94,95], despite the fact that some population genetics studies showed differentiation across the similar Tanaka line or the Tanaka-Kaiyong line [96,97].…”

Evaluating Population Genetic Structure and Demographic History of Quercus spinosa (Fagaceae) Based on Specific Length Amplified Fragment Sequencing

“…The organisms could be affected by complex ecological factors in the natural habitat (Bailey et al, 2013; Xu, 2015). Environmental heterogeneity has the potential to maintain intraspecific divergence and acts as an important driver for generating biological diversity (Fan et al, 2013; Ju et al, 2018). The ecological differentiation through adaptation to local environment reflects a balance between natural selection and the homogenization effect of the gene flow (Slatkin, 1987; Garant et al, 2007).…”