DEPARTMENT OF ANIMAL SCIENCE

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Author: search.filters.author.Osaiyuwu, O.H.Subject: search.filters.subject.Genetic diversity

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    Genetic diversity at four Nigerian sheep breeds assessed by variation of albumin and carbonic anhydrase in cellulose acetate electrophoretic systems
    (Faculty of Agriculture, 2018) Osaiyuwu, O.H.; Akinyemi, M. O.; Salako, A.E.; Awobajo, O.K.
    The aim of the study was to evaluate the occurrence and distribution of variations in blood protein markers in sheep breeds in Nigeria and to evaluate the relationships that exist among them. Atotal of 100 sheep comprising of twenty-five each of Balami, Uda, Yankassa and West African Dwarf (WAD) breeds were sampled for biochemical studies. Blood was collected to determine variations at the Albumin and Carbonic Anhydrase (CA) structural protein loci using F S A B cellulose acetate electrophoresis. All tested loci were polymorphic yielding four allelic variants (CA , CA , Alb , and Alb ) at the two protein loci. Genetic variability in the studied population was accessed using heterozygosity (observed – Ho and expected – He), effective number of alleles (Ne), fixation index (F) and gene flow (Nm). Genotypic frequencies ranged from 0.01 to 0.62 for CA and 0.25 to 0.49 for Alb loci. Estimated heterozygosity values ranged from 0.32±0.28 at Balami sheep to 0.70±0.22 in WAD with a global average estimated at 0.43±0.09 for all the breeds studied. The gene flow values for each of the loci studied were 0.82 and 1.24 for Alb and CA, respectively, with an average value of 1.03. The results showed that Yankassa and Balami sheep populations are more genetically (Nei's genetic identify value – 0.99) alike compared to Yankassa and WAD (0.73). Based on the values of heterozygosity (mean He =0.70 and Ho =0.45) assessed by variation of albumin and carbonic anhydrase the most genetic diverse is WAD sheep breed among the studied populations.
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    Genetic Relationship among Indigenous Goat Populations in Nigeria based on Cellulose Acetate Electrophoresis Systems
    (2018) Ganiyu, O.; Osaiyuwu, O.H.; Akinyemi, M.O.; Salako, E.A.
    Genetic diversity is the baseline for survivability and improvement of livestock in a wide array of environments. Variations among Red Sokoto, Sahel and WAD goats was determined using 5ml of blood collected by jugular venipuncture from 150 randomly selected goats (50 goats per breed). The samples were subjected to Cellulose Acetate Electrophoresis to determine the genetic variants of Haemoglobin (Hb), Transferrin, Carbonic Anhydrase, Albumin, Esterase 1, Esterase 3 and Alkaline phosphatase. Allele frequencies, similarity indices as well as genetic distances among the breeds were estimated. All the breeds in this study were polymorphic for Haemoglobin, Transferrin, Carbonic Anhydrase, Albumin, Alkaline phosphatase and Esterase 1 except WAD which was monomorphic for Alkaline phosphatase. The frequencies of HbA was considerably higher in Red Sokoto and WAD while frequencies of HbB were higher in Sahel goat population. The significant deviations from HWE (P<0.05, P<0.01 and P<0.001) was observed for some of the loci within the breeds. Genetic distance (D) obtained in this study ranged between 0.0648 and 0.1579 which indicates little genetic differentiation between the breeds. The results of this current study suggest that genetic improvement will be better achieved if WAD and Sahel goats are crossed.
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    Genetic structure of indigenous sheep breeds in Nigeria based on electrophoretic polymorphous systems of transferrin and haemoglobin
    (2018) Osaiyuwu, O.H.; Salako, E.A.
    The study used 100 indigenous sheep comprising 25 Balami, 25 Uda, 25 Yankassa and 25 West African Dwarf breeds reared extensively. The blood samples were taken from Vena Jugularis, processed according to standard procedure and transferrin and haemoglobin examined using cellulose acetate electrophoresis. The observed allele frequencies and genotypes (%) were tested with Hardy-Weinberg’sEquilibrium (χ2). Seven alleles TfA, TfB, TfC, TfD, TfE, TfGand TfPcontrolling 23 genotypes were observed at the transferrin locus while two haemoglobin alleles (HbAand HbB) controlling three phenotypes HbAA, HbAB and HbBB were detected. Except for the West African Dwarf sheep, all the samples indicated genetic equilibrium revealed by significant difference between observed and expected genotypes at both loci. The observed significant difference between the frequencies of alleles and genotypes at the two studied loci in the West African Dwarf sheep can be used as a source of genetic diversity during selection for improvement. The phylogenetic analysis as viewed by the tree topology suggests that the Balami and Uda may have had the same migration route or may have been the same breed which hadonly just recently branched off through adaptive. Also, the West African Dwarf sheep may have been the first to branch off the path of migration and thus had more clearly defined migration route or origin.