title: Evidence for balanced linkage of X chromosome polygenes in a natural population of Drosophila.
abstract: Extensive levels of polygenic variation can be maintained in a population without creating a severe segregational load. One way to account for this is that the alleles are arranged on a chromosome so that different regions balance each other phenotypically. To test whether this occurs in a natural population, we isolated ten Drosophila melanogaster X chromosomes and mapped regions of polygenic activity affecting sternopleural bristle number. The chromosomes fell into a small number of groups based upon the similarity of their distributions of polygenic activity. The results are consistent with a model in which a large proportion of the variation can be attributed to a small number of segregating chromosome regions and in which the chromosomes show internal balance.
authors.affiliation: Department of Zoology, University of Oklahoma, Norman 73019.
authors.forename: J N
authors.initials: JN
authors.lastname: Thompson
authors.forename: J J
authors.initials: JJ
authors.lastname: Hellack
authors.forename: R R
authors.initials: RR
authors.lastname: Tucker
mesh_terms: D000818:Animals; D003433:Crosses, Genetic; D004331:Drosophila melanogaster / Q000235:genetics; D005260:Female; D008040:Genetic Linkage; D014644:Genetic Variation / Q000235:genetics*; D005828:Genetics, Population; D008297:Male; D008957:Models, Genetic; D014960:X Chromosome