title: High genetic variability of esterase loci in natural populations of Parus major, P. caeruleus, and P. ater.
abstract: In Parus major, P. caeruleus, and P. ater the genetic variation of 16 isozyme loci was determined. The focus was on esterases that show high phenotypic variation in natural populations of these species. The degree of heterozygosity of the "non-esterase" loci was 0.029 +/- 0.008 (P. major); 0.023 +/- 0.012 (P. caeruleus), and 0.034 +/- 0.034 (P. ater). Including the esterase loci with up to six alleles per locus the overall degree of heterozygosity increased to 0.130 +/- 0.056 (P. major); 0.143 +/- 0.067 (P. caeruleus), and 0.194 +/- 0.090 (P. ater). We explain the high level of variability of esterases by gene amplification and subsequent selection for high allelic heterogeneity. Substrate specificity of loci is assumed to allow for multiple resistance against various toxic components. Large allelic valiation of esterases, therefore, increases the fitness of Parus species and allows for utilizing new food resources.
authors.affiliation: Division of General Human Genetics, Institute of Anthropology and Human Genetics, University of Tübingen, Wilhelmstrasse 27, D-72074 Tübingen, Germany.
authors.forename: Simon
authors.initials: S
authors.lastname: Driesel
authors.forename: Lutz
authors.initials: L
authors.lastname: Bachmann
authors.forename: Michael
authors.initials: M
authors.lastname: Stauss
authors.forename: Gernot
authors.initials: G
authors.lastname: Segelbacher
authors.forename: Doris
authors.initials: D
authors.lastname: Flach
authors.forename: Jürgen
authors.initials: J
authors.lastname: Tomiuk
authors.forename: Jost
authors.initials: J
authors.lastname: Kömpf
mesh_terms: D000483:Alleles; D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D004950:Esterases / Q000235:genetics*; D005784:Gene Amplification; D014644:Genetic Variation; D005828:Genetics, Population; D005858:Germany; D006579:Heterozygote; D007525:Isoelectric Focusing; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D011110:Polymorphism, Genetic; D012189:Retrospective Studies; D012641:Selection, Genetic; D020308:Songbirds / Q000235:genetics*; D013045:Species Specificity; D013379:Substrate Specificity
chemical_list: D007527:Isoenzymes; D004950:Esterases