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Title: Genetical studies on the inheritance of selected traits in Oreochromis niloticus and red tilapia
Author: Abella, T. A.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1994
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Abstract:
Four studies in Oreochromis niloticus and red tilapia on various aspects of quantitative and qualitative genetics as it relates to aquaculture were conducted. Allozyme variation was assessed in selected and control lines of O.niloticus using six diagnostic loci. Significant differences in allele frequencies in Ada, Ap, Est were observed between lines. The selected line deviated from the Hardy-Weinberg Equilibrium at the Ada and Ap loci while the control line deviated only in locus Ada. Two separate experiments in fluctuating asymmetry in selected lines and strains of O.niloticus were carried out to determine whether the domestication process has altered the developmental stability of the morphological characters in two selected lines and three African strains of O.niloticus. Tests for signed differences in the distribution of morphological characters between fish homozygous or heterozygous at each polymorphic loci were comparable between the two lines; on the other hand the three strains of O.niloticus showed significant differences in most morphological characters studied. No general pattern in the relationship between variances of morphological characters in the two selected lines and three strains of O.niloticus was observed. A two-way selection for sex ratio in red tilapia was conducted to unravel information on the sex determining mechanisms in tilapia. A positive response to selection on the basis of the linear relationship was achieved in this study indicating that sex ratio is somehow controlled by polygenic genes. A colour inheritance study was conducted in red tilapia. The intention of the study was to know the mode of colour inheritance in Philippine Red tilapia. The resuls from this study suggest that red coloration in this group of Philippine red tilapia is controlled either by complete or incomplete dominance and follows a simple Mendelian group inheritance.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.635836  DOI: Not available
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