Abstract
Electrophoretic examination of a natural population sample of 332 mussels (Mytilus trossulus) revealed ten active allozyme alleles for the octopine dehydrogenase (Odh) locus and a statistically significant (P<0.005) departure from expected genotypic proportions caused by a deficiency of heterozygous genotypes. In vitro specific activity for octopine dehydrogenase (E.C. 1.5.1.11) was determined for 207 mussels representing 17 different Odh genotypes. Odh heterozygotes had an average specific activity that was 19% greater than that of apparently homozygous genotypes, a significant (P<0.05) difference. Electrophoretic examination of a natural population sample of 209 oysters (Crassostrea virginica) revealed 23 active allozyme alleles for the leucine aminopeptidase-2 (Lap-2) locus and a non-significant (P>0.05) deficiency of heterozygous genotypes. In vitro specific activity for leucine aminopeptidase (E.C. 3.4.-.-) was determined for 89 oysters representing 19 different Lap-2 genotypes. Lap-2 heterozygotes had an average specific activity that was 56% greater than that of homozygous genotypes, a significant (P<0.0001) difference. Possible explanations for the apparent overdominance in enzyme specific activity and the deficiency of heterozygotes include null alleles, molecular imprinting and aneuploidy.
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Bradford, M. M., 1976. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal. Biochem. 72: 248–254.
Bulnheim, H. P. & Gosling, E., 1988. Population genetic structure of mussels from the Baltic sea. Helgolander Meeresunters. 42: 113–129.
Chakraborty, R., 1989. Can molecular imprinting explain heterozygote deficiency and hybrid vigor? Genetics 122: 713–717.
Foltz, D. W., 1986a. Null alleles as a possible cause of heterozygote deficiences in the oyster Crassostrea virginica and other bivalves. Evolution 40: 869–870.
Foltz, D. W., 1986b. Segretation and linkage studies of allozyme loci in pair crosses of the oyster Crassostrea virginica. Biochem. Genet. 24: 941–956.
Gäde, G. & Grieshaber, M., 1975. Partial purification and properties of octopine dehydrogenase and the formation of octopine in Anodonta cygnea L. J. comp. Physiol. 102: 149–158.
Gäde, G. & Grieshaber, M. K., 1986. Pyruvate reductases catalyze the formation of lactate and opines in anaerobic invertebrates. Comp. Biochem. Physiol. 83B: 255–272.
Gaffney, P. M., Scott, T. M., Koehn, R. K. & Diehl, W. J., 1990. Interrelationships of heterozygosity, growth rate and heterozygote deficiencies in the coot clam, Mulinia lateralis. Genetics 124: 687–699.
Gart, J. J. & Nam, J., 1988. The equivalence of two tests and models for HLA data with no observed double blanks. Biometrics 44: 869–873.
Gillespie, J. H. & Langley, C. H., 1974. A general model to account for enzyme variation in natural populations. Genetics 76: 837–848.
Gosling, E. M., 1989. Genetic heterozygosity and growth rate in a cohort of Mytilus edulis from the Irish coast. Mar. Biol. 100: 211–215.
Hedrick, P. W., 1985. Genetics of populations. Jones & Bartlett, Boston.
Hilbish, T. J. & Koehn, R. K., 1985. Dominance in physiological phenotypes and fitness at an enzyme locus. Science 229: 52–54.
Kaeser, H. & Burns, J. A., 1981. The molecular basis of dominance. Genetics 97: 639–666.
Katoh, M. & Foltz, D. W., 1989. Biochemical evidence for the existence of a null allele at the leucine aminopeptidase-2 (Lap-2) locus in the oyster Crassostrea virginica (Gmelin). Genome 32: 687–690.
Koehn, R. K., 1991. The genetics and taxonomy of species in the genus Mytilus. Aquaculture 94: 125–145.
Koehn, R. K. & Gaffney, P. M., 1984. Genetic heterozygosity and growth rate in Mytilus edulis. Mar. Biol. 82: 1–7.
Koehn, R. K., Bayne, B. L., Moore, M. N. & Siebenaller, J. F., 1980. Salinity related physiological and genetic differences between populations of Mytilus edulis. Biol. J. Linn. Soc. 14: 319–334.
Mallet, A. L., Zouros, E., Gartner-Kepkay, K. E., Freeman, K. R. & Dickie, L. M., 1985. Larval viability and heterozygote deficiency in populations of marine bivalves: evidence from pair matings of mussels. Mar. Biol. 87: 165–172.
McDonald, J. H. & Koehn, R. K., 1988. The mussels Mytilus galloprovincialis and M. trossulus on the Pacific coast of North America. Mar. Biol. 99: 111–118.
McPherson, G. A., 1985. Analysis of radioligand binding experiments: a collection of computer programs for the IBM PC. J. Pharmacol. Meth. 14: 213–228.
Mitton, J. B. & Grant, M. C., 1984. Associations among protein heterozygosity, growth rate, and developmental homeostasis. Ann. Rev. Ecol. Syst. 15: 479–499.
Paigen, K., 1979. Acid hydrolases as models of genetic control. Ann. Rev. Genet. 13: 417–466.
Pogson, G. H., 1989. Biochemical characterization of genotypes at the phosphoglucomutase-2 locus in the Pacific oyster, Crassostrea gigas. Biochem. Genet. 27: 571–589.
Pogson, G. H., 1991. Expression of overdominance for specific activity at the phosphoglucomutase-2 locus in the Pacific oyster, Crassostrea gigas. Genetics 128: 133–141.
Read, S. M. & Northcote, D. H., 1981. Minimization of variation in the response to different proteins of the Coomassie Blue G dye-binding assay for protein. Anal. Biochem. 116: 53–64.
Reed, T. E. & Schull, W. J., 1968. A general maximum likelihood estimation program. Amer. J. Hum. Genet. 20: 579–580.
Sarver, S. K. & Loudenslager, E. J., 1991. The genetics of California populations of the blue mussel: further evidence for the existence of electrophoretically distinguishable species or subspecies. Biochem. Syst. Ecol. 19: 183–188.
SAS, 1985. SAS User's Guide: Statistics. Version 5 Edition. SAS Institute, Inc., Cary, North Carolina.
Selander, R. K., Smith, M. H., Yang, S. Y., Johnson, W. E. & Gentry, J. B., 1971. Biochemical polymorphism and systematics in the genus Peromyscus. I. Variation in the old field mouse (Peromyscus polionotus). Stud. Genet. 6: 49–90.
Singh, S. M. & Zouros, E., 1978. Genetic variation associated with growth rate in the American oyster (Crassostrea virginica). Evolution 32: 342–353.
Skibinski, D. O. F., Beardmore, J. A. & Cross, T. F., 1983. Aspects of the population genetics of Mytilus (Mytilidae; Mollusca) in the British Isles. Biol. J. Linn. Soc. 19: 137–183.
Sokal, R. R. & Rohlf, F. J., 1981. Biometry, second edition. W. H. Freeman & Co., San Francisco.
Thiriot-Quievreux, C., 1984. Karyotypes of some Ostreidae and Mytilidae (Bivalvia). Malacologia 25: 465–476.
Thiriot-Quievreux, C., 1986. Study of aneuploidy in spats of Ostreidae (Bivalvia). Genetica 70: 225–231.
Thiriot-Quievreux, C., Noel, T., Bougrier, S. & Dallot, S., 1988. Relationships between aneuploidy and growth rate in pair matings of the oyster Crassostrea gigas. Aquaculture 75: 89–96.
Young, J. P. W., Koehn, R. K. & Arnheim, N., 1979. Biochemical characterization of ‘LAP’, a polymorphic aminopeptidase from the blue mussel, Mytilus edulis. Biochem. Genet. 17: 305–323.
Zouros, E., 1987. On the relation between heterozygosity and heterosis: an evaluation of the evidence from marine mollusks. Isozymes 15: 255–270.
Zouros, E. & Foltz, D. W., 1984. Possible explanations of heterozygote deficiency in bivalve molluses. Malacologia 25: 583–591.
Zouros, E. & Foltz, D. W., 1987. The use of allelic isozyme variation for the study of heterosis. Isozymes 13: 1–59.
Zouros, E., Romero-Dorey, M. & Mallet, A. L., 1988. Heterozygosity and growth in marine bivalves: further data and possible explanations. Evolution 42: 1332–1341.
Zouros, E., Singh, S. M. & Miles, H. E., 1980. Growth rate in oysters: an overdominant phenotype and its possible explanations. Evolution 34: 856–867.
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Sarver, S.K., Katoh, M. & Foltz, D.W. Apparent overdominance of enzyme specific activity in two marine bivalves. Genetica 85, 231–239 (1992). https://doi.org/10.1007/BF00132275
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DOI: https://doi.org/10.1007/BF00132275