We confirmed heightened condition dependent expression of sex comb bristle number and its female homologue (distal transverse row bristles) as compared to non- sex sternopleural bristles. First, in order to test for condition dependence, diet was manipulated in a set of ten Drosophila melanogaster full-sib families. Genetic architecture of variation underlying male sex comb bristle number, a rapidly evolving secondary sexual character of Drosophila, was examined. PMID:19833123Ĭondition dependence and the nature of genetic variation for male sex comb bristle number in Drosophila melanogaster.Īhuja, Abha De Vito, Scott Singh, Rama S We discuss the genetic and molecular definition of ETPs, and suggest that the function of Asxl1 depends on its cellular context. Hox a4, a7, and c8 are derepressed in Asxl1tm1Bc mutants in the antero-posterior axis, but Hox c8 expression is reduced in the brain of mutants, consistent with Asxl1 being required both for activation and repression of Hox genes. Transformations of the axial skeleton are enhanced in compound mutant embryos for the Polycomb group gene M33/Cbx2. The mutant embryos exhibit simultaneous anterior and posterior transformations of the axial skeleton, consistent with a role for Asxl1 in activation and silencing of Hox genes. We used a targeted mouse mutant line Asxl1tm1Bc to determine if Asxl1 is required to silence and activate Hox genes in mice during axial patterning. Asxl1 is required for normal adult hematopoiesis however its embryonic function is unknown. There are 3 murine homologs of Asx called Additional sex combs-like1, 2, and-3. The Additional sex combs ( Asx) gene of Drosophila behaves genetically as an enhancer of trithorax and Polycomb (ETP) in displaying bidirectional homeotic phenotypes, suggesting that is required for maintenance of both activation and silencing of Hox genes. Īdditional sex combs-like 1 belongs to the enhancer of trithorax and Polycomb Group and genetically interacts with Cbx2 in miceįisher, C.L. Asx(P1) shows an unusual phenotype in that anterior and posterior homeotic transformations are seen in the same individuals, suggesting that Asx(P1) might upset. Asx is required for normal determination of segment identity. To better understand the function of Asx, we have isolated nine new alleles, each of which acts like a gain of function mutation. W.Īdditional sex combs ( Asx) is a member of the Polycomb group of genes, which are thought to be required for maintenance of chromatin structure.
Genetic Analysis of the Additional Sex Combs Locus of Drosophila Melanogaster
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