Page 56 - University of Pretoria RESEARCH REVIEW 2018

Conserving endemic species
and ecosystem processes
Cora Stobie, Department of Biochemistry, Genetics and Microbiology
Despite being a water- scarce country, South Africa’s extensive freshwater ecosystems harbour rich aquatic biodiversity.
Molecular Ecology and Evolution Programme graduate, Dr Cora Stobie, focussed her PhD research primarily on an iconic group of endemic freshwater fish known as yellowfish (genus Labeobarbus).
Yellowfishes are highly popular in South Africa, both for subsistence
and recreational purposes. They are also used as indicators of river health – their presence indicating low water pollution and few alien fish species. For these reasons, conservation management of yellowfish in freshwater systems is needed.
The genus is particularly interesting from a genetics perspective as all the species are hexaploid; i.e., they have six sets of genetic material, unlike diploid animals (including humans) that have two. This greatly complicates many forms of genetic analysis, and necessitated forays
into next-generation sequencing, and restriction-site associated DNA sequencing, to bypass some of these difficulties.
Cora has subsequently shown that
L. natalensis, the KwaZulu-Natal yellowfish, is divided in two major genetic lineages and five distinct populations across a broad regional habitat separated by drainage systems. These findings, published in Ecology and Evolution in 2018, have important conservation implications. She also mined the genome sequencing data to reconstruct partial mitochondrial genomes for three species – L. natalensis and the Orange-Vaal yellowfishes, L. aeneus and the threatened L. kimberleyensis. The genetic analyses uncovered signals of divergence, hybridisation, introgression and even a recent translocation event between drainage systems. With her MEEP team co- authors, this work was published online in Molecular Ecology Resources in 2018.
Taken together, the two papers indicate that the distribution of genetic diversity can inform water resource management (among others, setting guidelines for inter-basin
water transfers), and translocation policies for species. The northern and southern river systems across KwaZulu-Natal are separate hotspots of diversity, and deserving of special protection to maintain evolutionary and ecological processes.
The Conservation Genetics Specialist Group (CGSG), which functions under the umbrella of the Species Survival Commission of the International Union for the Conservation of Nature, launched its Africa chapter in the KwaZulu-Natal midlands in November 2018. The aim of this specialist group is to promote the use of genetics in conservation management and policy, and thereby to assist the Commission in the development and analysis of genetic data in conservation. Four UP academics are members of the Africa group: Professors Paulette Bloomer, Catherine Sole and Brenda Wingfield, and Dr Thierry Hoareau.
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