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Protein polymorphism in quail populations selected for large body size
Animal Blood Groups and Biochemical Genetics
|January 1, 1980
Summary
Genetic analysis of enzyme polymorphism in selected (P) and control (C) chicken lines revealed differences in amylase, alkaline phosphatase, and albumin loci. The selected line showed reduced genetic diversity and a specific amylase phenotype, indicating selection impacts enzyme gene frequencies.
Area of Science:
- Animal Genetics
- Biochemistry
- Poultry Science
Background:
- Enzyme polymorphism plays a crucial role in animal breeding and genetic diversity.
- Understanding genetic variation in enzyme loci is essential for evaluating the effects of selective breeding in poultry.
Purpose of the Study:
- To investigate and compare the genetic polymorphism of five enzyme loci in a selected line (P) and an unselected control line (C) of chickens.
- To assess the impact of selection on enzyme gene frequencies and heterozygosity.
Main Methods:
- Analysis of enzyme polymorphism at five loci: amylase, alkaline phosphatase, albumin, and two others.
- Zymogram classification for plasma amylase into nine phenotypes based on six bands.
- Calculation of gene frequencies for specific alleles (e.g., alkaline phosphatase Akp-2B, albumin AlbQ1, esterase-D Es-DS) in both lines.
- Estimation of heterozygosities and calculation of the relative inbreeding coefficient for the selected line.
Main Results:
- Polymorphism was observed at three loci in the control line (C) and two loci in the selected line (P).
- The selected line (P) exclusively exhibited the most active plasma amylase phenotype, unlike the control line (C) which showed all nine phenotypes.
- Gene frequencies for alkaline phosphatase and albumin showed variations between the lines, with the selected line having a higher frequency of the AlbQ1 allele.
- Esterase-D allele frequencies differed, with Es-DS dominant in the control line and Es-DF in the selected line.
- Heterozygosity was lower in the selected line (0.1560) compared to the control line (0.2258), resulting in a relative inbreeding coefficient of 0.31 for the selected line.
Conclusions:
- Selective breeding in the P line has led to a reduction in genetic diversity and a fixation of specific enzyme phenotypes, particularly for plasma amylase.
- The observed differences in enzyme gene frequencies and heterozygosity highlight the genetic consequences of artificial selection in poultry populations.
- Further research into the functional significance of these enzyme polymorphisms in relation to economically important traits is warranted.