High genetic diversity and population differentiation in Clarias gariepinus of Yala Swamp: evidence from mitochondrial DNA sequences

Abstract

In order to improve the conservation and sustainable utilization of the African catfish Clarias gariepinus of the Yala Swamp in Kenya, genetic diversity and population structure of Lakes Kanyaboli and Namboyo populations of the species were studied using DNA sequences of the mitochondrial D-loop control region. Genetic diversity inferred as haplotype and nucleotide diversities and number of singletons and shared haplotypes was higher in the Lake Kanyaboli population (LKG) than the Lake Namboyo population (LNG) of C. gariepinus. Thirty-one haplotypes were inferred, of which 25 (80·6%) were private or singletons, while only six (19·4%) haplotypes were shared between LKG and LNG. Both populations were differentiated, with F value that was significantly different from zero (P < 0·05). Two clusters were inferred both from the maximum likelihood tree and the spanning networks of phylogenetic relationships of haplotypes. Mismatch distribution for total sample was multi-modal but individually, distributions were uni-modal in LKG, but multimodal in LNG. The mean ± s.d. raggedness index for both populations was 0·085 ± 0·098 and not significantly different from zero (P > 0·05). Individual raggedness indices were 0·015 and 0·154 for LKG and LNG respectively. Fu's F was negative for both populations, with LKG recording -14·871, while LNG had -2·565, significantly different from zero for LKG (P < 0·05), but the value for LNG was not significant (P > 0·05). Tajima's D was negative for both populations, with LKG recording -1·734, while LNG had -1·136. Standardized square differences (SSD) were 0·001 for LKG and 0·048 for LNG and non-significant between them (P > 0·05). Values between all populations were also not significantly different (P > 0·05), mean ± s.d. SSD 0·025 ± 0·033.

Genetic diversity and population structure of selected lacustrine and riverine populations of African catfish, Clarias gariepinus (Burchell, 1822), in Kenya

“…The higher number of haplotypes in the Nyando River population compared to populations from other rivers may be due to its larger drainage basin of 3,587 km 2 (Gathenya et al., 2011), and the fact that the river flows throughout the year. These characteristics are likely to reduce mortality in the population, and help to maintain higher genetic diversity (Barasa et al., 2016). On the other hand, Tana River which is equally large and perennial had lower number and diversity of haplotypes than Nyando River, and this could be attributed to habitat fragmentation through damming of the river for electricity generation (Vogl et al., 2016).…”

“…However, the efficiency of artificial propagation of the species at hatcheries is reduced by poor survival of C. gariepinus larvae (Sulem et al., 2006). Recent studies to address this challenge have focused on genetic characterization of C. gariepinus populations in order to identify suitable populations for use as brood stock (Barasa et al., 2014, 2016; 2017; Ojiambo, 2015) and those populations in need of conservation (Barasa et al., 2017).…”

Genetic diversity of the North African catfish, Clarias gariepinus (Burchell, 1822) hatchery stocks in Thailand

“…This indicated the existence of germplasm diversity of Cg which is essential for genetic improvement. In fact, Cg possesses high genetic diversity both in natural habitats and hatcheries in its native countries 9,33 . However, the genetic diversity among populations of the introduced stocks have depended on acquired genetic diversity of the founder stocks as well as gene-flow among them.…”

Genetic variability and population structure of Capoeta gracilis (Keyserling 1861) populations in the southern basin rivers of the Caspian Sea as revealed by the mtDNA sequences

“…Existence of genetic variability seems to be necessary for the survival of a species in its environment. Loss of genetic variation in species can lead to reduction or even total loss of populations and species and biodiversity loss can occur at a higher and faster rate in smaller and isolated populations (Barasa et al, 2016). Therefore, population genetic or species molecular surveys are essential for the conservation programs on different species (Wang et al, 2007;Diz and Presa, 2009).…”