Understanding the level of genetic diversity in any population is an important requisite towards strategizing measures for conservation and improvement of stocks. This study focused on the assessment of phylogenetics and molecular divergence of tilapia fish species obtained from two populations (Domita in South-South and Odeda in South-West, Nigeria) using the displacement loop (D-loop) and cytochrome b region of the mitochondrial deoxyribonucleic acid (mtDNA). A total of 28 samples (15 from South-South and 13 from SouthWest) were used for the genetic analysis. DNA was extracted from the tissue of all the samples using Quik-gDNA TM miniPrep kit. The D-loop containing the hypervariable region was sequenced for all samples from the two populations, while cytochrome b (Cyt b) region of mtDNA was only sequenced for samples from South-South population. Chromatograms of the sequences were viewed and edited using Bioedit software. Multiple sequence alignment was carried out using molecular evolutionary genetic analysis (MEGA) software before subsequent genetic analyses. Phylogenetic analysis grouped the samples into two clusters based on population. Also, when the two mitochondrial regions were pooled together, they clustered into two major groups based on mitochondrial regions. Analysis of molecular variance (AMOVA) revealed 37.32% variation within population and 62.68% variation among population with a significant fixation index of 0.627 (p < 0.05).

The comparative study of egg quality traits of black-skinned and white-skinned ectotypes of snails (Archachatina marginata) based on four whorls were studied using sixty adult snails. The snails were managed in captivity for three months using hutches, embedded with steriled, loamy soil to generate eggs for the study. Egg quality traits evaluated include number of eggs laid, egg weight, length and width. The snails were divided into two mating groups, black-skinned x blackskinned and white-skinned x white-skinned ectotypes of snails. Data collected were subjected to t-test. Results showed that the black-skinned ectotype laid 112 eggs from 13 clutches, while the white-skinned ectotype laid 98 eggs from 11 clutches. The results of the egg quality traits analyzed showed high significant differences (p<0.05) between the two ectotypes of snails based on four whorls. The results of the phenotypic correlation of the egg quality traits also revealed a highly significant (p<0.001) mean number of egg, mean egg weight, length and width between the two ectotypes of snails. The highly and positive correlation between the egg quality traits could suggest that there are direct relationships between the traits and selection for one trait leads to improvement of the other trait. It is recommended that snails with 5, 6 and 7 whorls should be used for analysis of egg quality traits since the number of whorls are yet to be used as a standard for estimating the age of snails.

No abstract

No abstract

This noble research provides information on the genetic differentiation between black-skinned and white-skinned ectotypes of giant African land snails (Archachatina marginata). Ten (10) snails consisting of five (5) black-skinned and five (5) white-skinned ectotypes were examined by using the random amplified polymorphic DNA (RAPD) technique. Five (5) primers (OPAD-09, OPAE-04, OPAE-05, OPAF-07 and OPAF-09) were screened and selected to amplify DNA from the ten (10) samples of snails. A total of 31 bands were generated from the two snail types, out of which 14 bands were generated from the black-skinned ectotype, while 17 bands were from the whiteskinned ectotype. The DNA banding between the two ectotypes showed no statistical difference (P > 0.05) between the black-skinned and the white-skinned ectotypes of Archachatina marginata. There were however, relative high genetic differences in numerical number of bands between the two ectotypes. This implied that the genetic similarities are relatively low. The high genetic differences between the two ectotypes of Archachatina marginata snails studied signaled high level of genetic diversity and heterogeneity among the giant African land snails (GALS).