Population structuring in mountain zebras (<Emphasis Type="Italic">Equus zebra</Emphasis>): The molecular
consequences of divergent demographic histories |
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Authors: | Email author" target="_blank">Yoshan?MoodleyEmail author Eric H?Harley |
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Institution: | (1) Wildlife Genetics Unit, University of Cape Town, Observatory, Cape Town, 7925, Republic of South Africa;(2) School of Biosciences, Main Building, Cardiff University, Cathays Park, CF10 3TL Cardiff, UK |
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Abstract: | The endangered mountain zebra (Equus zebra) is endemic to the semi-arid inhospitable mountainous escarpments of southern Africa. The species is divided taxonomically
into two geographically separated subspecies, each with differing recent population histories. In Namibia, Hartmann’s mountain
zebra (E. z. hartmannae) is common and occurs in large free-ranging populations, whereas in South Africa, prolonged hunting and habitat destruction
over the last 300 years has decimated populations of the Cape mountain zebra (E. z. zebra). In this study, we investigate the consequences of these divergent demographic histories for population genetic diversity
and structure. We also examine the phylogeographic relationship between the two taxonomic groups. Genetic information was
obtained at 15 microsatellite loci for 291 individuals from a total of 10 populations as well as 445 bp of the mitochondrial
control region sequence data from 77 individuals. Both model-based and standard analytical approaches were used to examine
the data. Both types of marker returned levels of diversity and structure that were consistent with population history. Low
genetic variation within individual Cape mountain zebra populations, the characteristic indicator of population fragmentation
and drift, was offset by moderate variation in the entire E. z. zebra sample. This implies that higher levels of diversity still exist within the Cape mountain zebra gene pool. A management strategy
that entailed the mixing of aboriginal populations is therefore advocated in order to halt the further loss of Cape mountain
zebra genetic diversity. Allele frequencies in Hartmann’s mountain zebra were relatively resilient to demographic fluctuations.
Due to the high incidence of mitochondrial haplotype sharing between populations, the hypothesis that Cape and Hartmann’s
mountain zebra mitochondrial lineages were reciprocally monophyletic was not supported. However, the presence of private alleles
at nuclear loci rendered the two subspecies genetically distinct evolutionary significant units. |
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Keywords: | Mountain zebra population structure conservation |
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