Warren R W, Nagy L, Selegue J, Gates J, Carroll S
Howard Hughes Medical Institute, University of Wisconsin-Madison 53706.
Nature. 1994 Dec 1;372(6505):458-61. doi: 10.1038/372458a0.
It has been proposed that the evolution of homeotic genes parallels, and to some degree directs, the evolution of segment diversity in the myriapod-insect lineage. But the discovery of discrete Antennapedia complex (ANT-C) and bithorax complex (BX-C) gene members in crustacea, chelicerates, annelids and various insects, as well as in vertebrates, indicates that the expansion and diversification of homeotic genes preceded the diversification of arthropods and insects. How, then, have these genes influenced the evolution of body plans? To address this question, we now examine homeotic gene expression and regulation in butterflies (Lepidoptera), which, unlike flies, possess larval abdominal limbs and two pairs of wings. We show that the difference in larval limb number between these insects results from striking changes in BX-C gene regulation in the butterfly abdomen, and we deduce that the wing-patterning genes regulated by Ultrabithorax have diverged in the course of butterfly and fly evolution. These findings have general implications for the role of homeotic genes in animal evolution.
有人提出，同源异型基因的进化与多足纲-昆虫谱系中体节多样性的进化平行，并且在一定程度上指导着后者的进化。但是，在甲壳纲动物、螯肢动物、环节动物、各种昆虫以及脊椎动物中发现了离散的触角足复合体（ANT-C）和双胸复合体（BX-C）基因成员，这表明同源异型基因的扩增和多样化先于节肢动物和昆虫的多样化。那么，这些基因是如何影响身体结构的进化的呢？为了解决这个问题，我们现在研究蝴蝶（鳞翅目）中的同源异型基因表达和调控，蝴蝶与苍蝇不同，具有幼虫腹部附肢和两对翅膀。我们发现，这些昆虫幼虫附肢数量的差异是由蝴蝶腹部BX-C基因调控的显著变化导致的，并且我们推断，由超双胸基因调控的翅膀图案形成基因在蝴蝶和苍蝇的进化过程中已经发生了分歧。这些发现对于同源异型基因在动物进化中的作用具有普遍意义。
