Peterson M D, Rogers B T, Popadić A, Kaufman T C
Howard Hughes Medical Institute, Indiana University, Department of Biology, Bloomington, IN 47405, USA.
Dev Genes Evol. 1999 Feb;209(2):77-90. doi: 10.1007/s004270050230.
During embryogenesis of the fruit fly, Drosophila melanogaster, the homeotic genes are required to specify proper cell fates along the anterior-posterior axis of the embryo. We cloned partial cDNAs of homologues of the Drosophila homeotic gene teashirt and five of the homeotic-complex (HOM-C) genes from the thysanuran insect, Thermobia domestica, and assayed their embryonic expression patterns. The HOM-C genes we examined were labial, Antennapedia, Ultrabithorax, abdominal-A and Abdominal-B. As the expression pattern of these HOM-C genes is largely conserved among insects and as Thermobia is a member of a phylogenetically basal order of insects, we were able to infer their ancestral expression patterns in insects. We compare the expression patterns of the Thermobia HOM-C genes with their expression in Drosophila and other insects and discuss the potential roles these genes may have played in insect evolution. Interestingly, the teashirt homologue shows greater variability between Thermobia and Drosophila than any of the HOM-C genes. In particular, teashirt is not expressed strongly in the Thermobia abdomen, unlike Drosophila teashirt. We propose that teashirt expression has expanded posteriorly in Drosophila and contributed to a homogenization of the Drosophila larval thorax and abdomen.
在果蝇黑腹果蝇的胚胎发育过程中，同源异型基因对于沿着胚胎的前后轴确定适当的细胞命运是必需的。我们从缨尾目昆虫嗜热衣鱼中克隆了果蝇同源异型基因teashirt及其同源异型复合体（HOM-C）基因中的五个基因的部分cDNA，并分析了它们的胚胎表达模式。我们检测的HOM-C基因有唇化基因、触角足基因、超双胸基因、腹A基因和腹B基因。由于这些HOM-C基因的表达模式在昆虫中基本保守，并且嗜热衣鱼是昆虫系统发育基部目之一的成员，我们能够推断它们在昆虫中的祖先表达模式。我们将嗜热衣鱼HOM-C基因的表达模式与其在果蝇和其他昆虫中的表达进行比较，并讨论这些基因在昆虫进化中可能发挥的潜在作用。有趣的是，teashirt同源物在嗜热衣鱼和果蝇之间表现出比任何HOM-C基因更大的变异性。特别是，与果蝇的teashirt不同，嗜热衣鱼的teashirt在腹部没有强烈表达。我们提出，teashirt的表达在果蝇中向后扩展，并导致了果蝇幼虫胸部和腹部的同质化。
