Demographic history and population genetic structure of Hagenia abyssinica (Rosaceae), a tropical tree endemic to the Ethiopian highlands and eastern African mountains

• Published in: Tree genetics & genomes Vol. 13; no. 4; p. 1
• Main Authors: Gichira, Andrew W., Li, Zhi-Zhong, Saina, Josphat K., Hu, Guang-Wan, Gituru, Robert W., Wang, Qing-Feng, Chen, Jin-Ming
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-08-2017; Springer Nature B.V
• Subjects: Biodiversity; Biomedical and Life Sciences; Biotechnology; Coefficient of variation; Demographics; Differentiation; Ecological effects; Ecological monitoring; Forestry; Gene flow; Genetic diversity; Genetic structure; Genetic variability; Heterogeneity; Highlands; Life history; Life Sciences; Microsatellites; Modelling; Mountains; Natural populations; Niches; Original Article; Plant Breeding/Biotechnology; Plant Genetics and Genomics; Plant populations; Population genetics; Population structure; Populations; Refugia; Species; Tree Biology; Population structure; Eastern Africa; Genetic diversity; Niche modeling; Afromontane forests
• ISSN: 1614-2942; 1614-2950
• DOI: 10.1007/s11295-017-1156-6

The distribution of genetic diversity among natural populations is significantly shaped by geographical and environmental heterogeneity. The key objectives of this study were to outline the population genetic structure and to investigate the effects of historical and current factors in shaping the population structure of an endemic tropical tree,
Hagenia abyssinica
. We used 11 polymorphic microsatellites to estimate genetic variability and evaluate gene flow among natural populations of
H. abyssinica
. Further, we employed ecological niche modeling approaches, to analyze the demographic history and map potential distributions of
H. abyssinica
during the Last Glacial Maximum and the present. Significant levels of genetic diversity (
H
O
 = 0.477,
H
E
= 0.439) were observed among the sampled locations. High coefficient of genetic differentiation (
F
ST
 = 0.32) and considerable genetic variation within the sampled locations (68.01%) were detected. Our results indicated the existence of three genetic groups with limited gene exchange and revealed positive correlations (
r
 = 0.425,
P
< 0.05) between genetic diversity and geo-graphic distance. The ecological niche modeling (ENM) results support the existence of three distribution zones during the Last Glacial Maximum (LGM), with high probability of occurrence (0.8–1.0), and indicated slight distribution disturbances during and after the LGM. The fundamental patterns of genetic diversity and population structuring of
H. abyssinica
result from a combination of both environmental and geographical factors, including long-term isolation by distance and characteristic life history of this species. Our ENM results identified three zones that could have served as glacial refugia for this species and lay a foundation for further studies, outlining demographic histories and population structures of Afromontane species.