Browsing by Author "Abban, E.K."
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Item Genetic Characterization and Early Life Culture Performance Evaluation of Four Ghanaian Populations of Tilapia Guineensis (Pisces; Cichlidae)(University of Ghana, 2004-07) Agyakwah, S.K.; Abban, E.K.; Koranteng, K.A.; Ofori-Danson, P.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Marine and Fisheries SciencesGenetic characteristics of four populations of the cichlid Tilapia guineensis were studied using allozyme (starch gel) electrophoresis and early life culture performance characterization to generate information on genetic structure and characteristics of major culture performance traits during early life of the species. Samples of the fish populations were collected from three freshwater reservoirs: (i) the Volta reservoir at Kpong, (ii) the Okye-Aminsa reservoir at Akotogua and (iii) the Ayensu reservoir at Okyereko; and a coastal open lagoon of the Volta system at Aglorkpovie. Observed heterozygosity (Ho) and polymorphism (P) of allozymes as indices of genetic diversity were relatively low in Akotogua (Ho = 0.077; P = 0.077) and Aglorkpovie (Ho = 0.077; P = 0.077) populations compared to those of Kpong (Ho = 0.308; P = 0.089) and Okyereko (Ho = 0.462; P = 0.087) populations. Early life culture performance characteristics of populations evaluated over 84 days showed significantly higher final mean length, weight gain and condition factor in Akotogua populations compared to growth characteristics of Aglorkpovie and Kpong populations. Results suggest that heterozygosity and polymorphism might be important in determining culture performance traits. Additionally, high genetic diversity did not confer high culture performance characteristics on the early life of the fish. The biochemical genetic structure and growth characteristics observed in Akotogua population identify it as a population with a potentially better early life culture performance that could be used by culturists for improvement of T. guineensis in aquaculture.Item Morphometric and Allozymic Characterisation and Genetic Variation in Three Species of Chrysichthys in Ghana(University of Ghana, 1996-08) Dade, M.K.; Vanderpuye, C.J.; Abban, E.K.; Addy, M.E.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Marine and Fisheries SciencesChrysichthys species have been characterised by previous investigators. Most often, characterisation has been based on morphological and meristic characters. These characters may be modified by environmental factors, thus making them difficult to use in characterising species. There is the need therefore to refine or supplement taxonomy based on morphological and meristic characteristics. In the present study, variation in meristic counts and twelve body proportion variables in three species of the Catfish, Chrysichthys from two river basins (Volta and Densu) in Ghana were evaluated for their reliability in separating the species. Position of the longest dorsal soft fin ray and the number of branched pectoral fin rays were found to be stable and dependable in the identification of the three species. Body proportion values showed wide ranges which overlap so much that they do not give precise identification of species. In addition to the moiphometric study, variation at 15 loci involving eleven proteins were studied by allozyme electrophoresis in each of the species to (i) identify loci that discriminate between species, (ii) estimate levels of genetic variation among C. auratus, C. nigrodigitatus and C. maurus, (iii) estimate phonetic relationships among populations and species, and (iv) indicate whether there are any significant differences in the genotypic frequencies of populations. Seven discriminating loci were found between C. auratus and either C. nigrodigitatus or C. maurus. At the loci investigated, genetic variation was generally low in all the species. It was highest in C. auratus and least in C. nigrodigitatus [Polymorphism, P, (l% criterion) = 0.178 in C. auratus, 0.133 in C. maurus and 0.089 in C. nigrodigitatus-, Heterozygosity, He, = 0.029 in C. auratus, 0.016 in C. maurus and 0.009 in C. nigrodigitatus]. There were no significant genetic differences between populations within C. auratus and C. nigrodigitatus (average gene diversity between populations, Dst, = 0.001 in both species). Again based on lod screened, the closest species genetically were C. nigrodigitatus and C. maurus (Genetic identity, I, = 0.999) while the most distant species were C. auratus and C. maurus (I = 0.525). There were no significant changes in the genotypic frequencies of the populations (X205 ranges from 0.020 to 2.292 for polymorphic loci).Item Population data of 23 Y chromosome STR loci for the five major human subpopulations of Ghana(International Journal of Legal Medicine, 2019-06-01) Ghansah, A.; Abban, E.K.; Hakim, H.M.; Khan, H.O.; Ismail, S.A.; Agyemang, A.D.; Mat, N.F.C.; Chambers, G.K.; Edinur, H.A.In this study, 268 samples for unrelated males belonging to the five major human subpopulation groups in Ghana (Akan, Ewe, Mole-Dagbon, Ga-Dangme and Guang) were genetically characterised for 23 Y chromosome short tandem repeat (STR) loci using the Powerplex® Y23 STR kit. A total of 263 complete haplotypes were recorded of which 258 were unique. The haplotype diversity, discriminating capacity and match probability for the pooled population data were 0.9998, 0.9627 and 0.0039, respectively. The pairwise genetic distance (RST) for the Ghanaian datasets and other reference populations deposited in the Y-STR Haplotype Reference Database (YHRD) were estimated and mapped using multidimensional scaling (MDS) plot. The Guang and Ewe were significantly different from the Akan, Mole-Dagbon and Ga-Dangme. However, the five Ghanaian datasets were all plotted close together with other African populations in the MDS data mapping.Item Population Genetics and Characterization of Cowpea Accessions (Vigna Unguiculata (L) Walp) from Three Agroecological Zones of Ghana Based on Isozyme(University of Ghana, 1996-10) Asante, I.K.; Laing, E.; Abban, E.K.; Jumah, A.; University of Ghana, College of Basic and Applied Sciences , School of Biological Sciences , Department of BotanyAllozyme variation in protein encoded at 22 loci was studied in 9 cowpea accessions from three agroecological zones of Ghana (namely Deciduous forest, Guinea savannah and Sudan savannah) by electrophoresis. In addition, variation in thirteen morphological agronomic traits of the accessions were studied. The results indicated that: (i) 21 out of 22 loci were polymorphic (95.5%); (ii) cowpea accessions displayed average estimates of mean alleles per locus, A = 5.00; mean expected heterozygosity, HL = 0.561±0.037, mean observed heterozygosity, H0 = 0.264±0.007; total genetic diversity, Ht = 0.648±0.032; mean Wright's fixation index, F1S = 0.573±0,. 096,- frequency of crosspollination, 0 . 244±0.067 (iii) Coefficient of genetic distance (Dm) based on allozyme data among Deciduous forest zone accessions ranged from 0.130 to 0.167 with a mean of 0.143±0.010, among Guinea savannah zone accessions the range was 0.101 to 0.190 with a mean of 0.140±0.021 and in Sudan savannah zone accessions the range was 0.163 to 0.285 with a mean of 0.235±0.030 Coefficient of meristic distance (Dm) based on meristic data among Deciduous forest zone accessions ranged from 0.063 to 0.285 with a mean of 0.103±0.017, among Guinea savannah zone accessions the range was 0.047 0.190 with a mean of 0.123±0.034 and among Sudan savannah zone accessions the range was 0.010 0.057 with a mean of 0.038±0.012. (iv) Deviations from Hardy-Weinberg equilibrium were found in several loci in some of the cowpea accessions (v) 86.5% of total genetic variation was found to be present within accessions while 13.4% resided among accessions. (vi) Allozymic and environmental variations were partly correlated; morphological and environmental factors were partially correlated. (vii) Allozyme variations in several gene loci and morphological variations were significantly correlated with and predictable by environmental variables, primarily related to geographic, temperature and moisture indices. Pattern of genetic variation within and between accessions suggested that: (a) climatic 'selection' plays a primary role in allozymic and morphological differentiation into ecologically adaptive patterns; (b) the environmental variation model seems to be a good predictor of genetic variation in cowpea accessions. Results suggested that use of isozyme technique can (a) lead to discovery of genetic markers for quantitative traits in cowpea breeding,- (b) help in collection, multiplication and regeneration of cowpea seed germplasm. Results further suggested that cowpea accessions from Sudan savannah zone of Ghana should serve as good source of genetic material for improvement of the sum of genetic variability in materials used in cowpea breeding.Item Taxonomy, Exploitation and Conservation of Dolphins in the Marine Waters of Ghana(University of Ghana, 2000-09) Debrah, J.S.; Vanderpuye, C.J.; Ofori-Danson, P.K.; Abban, E.K.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Marine and Fisheries SciencesLittle is known about dolphins present in Ghanaian coastal waters. Taxonomic status, catch rate, and impact of the fishery on these animals, are areas, which have remained virtually untouched by previous workers. The present study attempts to fill-in these gaps in knowledge. Studies conducted during 1998 -2000 revealed the presence of the following eight species in Ghanaian waters: Stenella clymene, Stenella attenuata, Steno bredanensis, Tursiops truncatus, Grampus griseus, Lagenodelphis hosei, Globicephala macrorhynchus, and Delphinus capensis. S. Chlymene emerged as the most abundant species. Dolphin catches were low with peak period in August and September. Demand for dolphin meat for human consumption and bait for the shark fishery increased during the period of study. Though laws designed to protect and conserve dolphins exist on the Ghanaian statutes, little effort is made to enforce them. An educational programme, which would sensitize fisher folk on the issue of conservation, is also absent. Morphological taxonomy proved very useful in discriminating between species of dolphins encountered but no single character was found to be suitable. A combination of morphological characters, however, proved most effective. It was difficult to use biochemical characters possibly because the Delphinidae family, exists as polymorphic form of the same species.