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Title:Linkage and Tissue Expression of Enzyme Loci in Interspecific Sunfish (Centrarchidae) Hybrids: Evolutionary and Quantitative Genetic Implications
Author(s):Pasdar, Manijeh
Department / Program:Genetics and Development
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Biology, Genetics
Abstract:Two species of sunfishes (Centrarchidae, Perciformes), green sunfish, G (Lepomis cyanellus), redear sunfish, R (L. microlophus), their reciprocal hybrids, and four different backcross progeny have been used to investigate the chromosomal locations of enzyme loci, the genetic basis for their differences in tissue expression between species, and the extent the enzyme activity levels in hybrids are related to heterotic effects in growth.
Linkage relationships of nine enzyme loci, aconitase (Acon), esterase (Est), glucosephosphate isomerase A and B (Gpi), glycerate-2-dehydrogenase (G2dh), malic enzyme (Me), phosphoglycerate kinase (Pgk), phosphoglucomutase (Pgm), and superoxide dismutase (Sod), have been investigated. A three-point linkage map comprising G2dh, Pgk and Sod is reported. The frequency of recombination between G2dh and Pgk and Pgk and Sod are estimated as 45.3% and 24.7%, respectively. The remaining six loci assort independently.
The extent of naturally occurring variations of enzyme locus expression within and between species was determined for three tissues (liver, muscle, eye) for four enzymes: malate dehydrogenase, lactate dehydrogenase, glucosephosphate isomerase, and phosphoglucomutase. Specific activities for most enzymes in hybrids were intermediate between those of the parental species. Significant differences in enzyme specific activity were detected among progeny of parental crosses as well as those of backcrosses. Variations in specific activity levels of different tissues were often unrelated. However, the alterations in specific activities of different enzymes within a tissue were often positively correlated. The tissue glucosephosphate isomerase activity differences appear not to be due to different functional contributions of the glucosephosphate isomerase allelic isozymes. Results of the cluster analysis of distribution of specific activities suggest a polygenic control of tissue enzyme specific activity levels.
Average body weight and growth rate were compared among the progeny of four parental crosses over a two-year period. After one growing season, RG hybrids showed the greatest growth followed by those of GR hybrid, redear and green sunfish. At the end of the second growing season, GR hybrids had the highest average weight followed by RG hybrids, redear and green sunfish.
No significant correlation was observed between growth and the tissue levels of enzyme locus expression for malate dehydrogenase, lactate dehydrogenase, glucosephosphate isomerase, and phosphoglucomutase enzymes.
Issue Date:1984
Description:103 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1984.
Other Identifier(s):(UMI)AAI8422794
Date Available in IDEALS:2014-12-16
Date Deposited:1984

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