生物谷報道：肢體的對稱和不對稱性,，以及肢體的發(fā)育形成都是有趣的研究課題。這篇研究報道發(fā)表在最新一期PNAS的封面上,，他們觀察到HOX基因直接決定了昆蟲的腿的發(fā)育,，請看報道：
Diversification of leg appendages is one of the hallmarks of morphological evolution in insects. In particular, insect hind (T3) legs exhibit a whole spectrum of morphological diversification, ranging from uniform to extremely modified. To elucidate the developmental basis of T3 leg evolution, we have examined the expression patterns of two homeotic genes, Ultrabithorax and abdominal-A (collectively referred to as UbdA), in a broad range of species. First, our results show that UbdA expression in hemimetabolous insects is localized only in specific T3 leg segments undergoing differential growth (compared to their foreleg counterparts). In contrast, in basal hexapod and insect lineages, the absence of the UbdA signal coincides with uniform leg morphology. The same situation exists in first instar larvae of holometabolous insects, in which absence of UbdA expression in the embryonic T3 legs is associated with the lack of larval T3 leg diversification. Second, there is a clear difference in the timing of expression between species with greatly enlarged T3 leg, such as crickets and grasshoppers, and species that exhibit more moderate enlargement of hind legs, such as mantids and cockroaches. In the former, the UbdA expression starts much earlier, coinciding with the elongation of T3 limb buds. In the latter, however, the UbdA expression starts at much later stages of development, coinciding with the establishment of distinct leg segments. These results suggest that diversification of insect hind legs was influenced by changes in both the spatial and temporal regulation of the UbdA expression.
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Najmus S. Mahfooz, Hua Li, and Aleksandar Popadic From the Cover: Differential expression patterns of the hox gene are associated with differential growth of insect hind legs
PNAS 2004 101: 4877-4882; published online before print March 23 2004, 10.1073/pnas.0401216101 [Full Text] [PDF]
