Genetic Diversity in the mtDNA control region and population structure of Chrysichthys nigrodigitatus from selected Nigerian rivers: Implications for conservation and aquaculture

Abstract

The genetic diversity and population structure of Chrysichthys nigrodigitatus were evaluated using a 443 base pair fragment of the mitochondrial control region. Among the eight populations collected comprising 129 individuals, a total of 89 polymorphic sites defined 57 distinct haplotypes. The mean haplotype diversity and nucleotide diversity of the eight populations were 0.966±0.006 and 0.0359±0.004, respectively. Analysis of molecular variance showed significant genetic differentiation among the eight populations (FST =0.34; P < 0.01). The present results revealed that C. nigrodigitatus populations had a high level of genetic diversity and distinct population structures. We report the existence of two monophyletic matrilineal lineages with mean genetic distance of 10.5% between them. Non-significant negative Tajima’s D and Fu’s Fs for more than half the populations suggests that the wild populations of C. nigrodigitatus underwent a recent population expansion, although a weak one since the late Pleistocene.

Morphological and Genetic Diversity Studies of Chrysichthys nigrodigitatus from the Cross River, Nigeria, Using Microsatellite Markers

“…Such reduction in the size of a population can reduce variations in a gene pool, leaving a limited number of species to pass on genes to offspring through sexual reproduction. Earlier studies of C. nigrodigitatus from Cross River region of the Niger Delta using mtDNA and AFLP analyses reached similar conclusions of low genetic diversity [9,10,26].…”

“…The use of molecular markers such as Mitochondria DNA, Random Amplification of Polymorphic DNA and Microsatellite DNA has greatly facilitated studies on the genetic structure, diversity and evolutionary divergence of different fish populations including Chrysichthys spp. [9,10,11,12] Microsatellite markers have been widely used because they are abundant and distributed throughout the genome, are highly polymorphic, suitable for detecting heterozygotes, are biparentally inherited and transferable among related taxa. In population genetics, their use has enhanced estimation of genetic diversity, parental relatedness, population structure and recent population history of different fish populations including Chrysichthys spp.…”

“…Unfortunately, despite the economic importance of C. nigrodigitatus species occurring in the Cross River Basin, eastern Niger Delta, there is paucity of information about their genetic background. Existing genetic diversity studies of C. nigrodigitatus in Nigeria either focused on other regions or were assessed using only a few samples from Cross River or using other marker types [10,12,14,17]. Therefore, the present study was done to document the morphological and genetic variations between two populations of C. nigrodigitatus from the Cross River system.…”

High genetic diversity and demographic history of captive Siamese and Saltwater crocodiles suggest the first step toward the establishment of a breeding and reintroduction program in Thailand

“…This star-like network might also imply the presence of a population bottleneck followed by a population expansion. Significant negative values for neutrality statistics also indicate population expansion [ 60 ]. This finding suggests that the captive crocodile populations originated from wild-caught crocodiles and were subsequently bred within each captive breeding program to produce a large number of individuals.…”

Molecular analysis of population and De Novo transcriptome sequencing of Thai medaka, Oryzias minutillus (Teleostei: Adrianichthyidae)

“…In molecular phylogenetics, this genetic differentiation marker has been utilized for fish populations, such as anchovies (Coilia ectenes taihuensis) in Taihu Lake, China (Zhang et al, 2017); brown chromis (Chromis multilineata) in the Western Atlantic Ocean of Brazil (Cruz et al, 2014); loaches (Lefua spp.) in Japan (Sakai et al, 2003); skipjack tuna (Katsuwonus pelamis) on the Indian coast (Menezes et al, 2012); bagrid catfish (Chrysichthys nigrodigitatus) from the Nigerian rivers (Nwafili and Gao, 2016); and African catfish (Clarias gariepinus) in Kenya (Nyunja et al, 2017). Similar to mitochondrial genes, cytochrome c oxidase subunit I (cox1 or co1) is a mitochondrial gene that is frequently used for population-level phylogenetic analyses or DNA barcodes in various animals (Razo-Mendivil et al, 2010;Hebert et al, 2003).…”