Developmental constraints and convergent evolution in Drosophila sex comb formation
Developmental constraints and convergent evolution in Drosophila sex comb formation
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DOI：
10.1111/j.1525-142x.2009.00320.x
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发表时间：
2009-03-01
影响因子：
2.9
通讯作者：
Larsen, Ellen W.
中科院分区：
文献类型：
--
作者：
Atallah, Joel;Liu, Nana Hou;Larsen, Ellen W.
果蝇中最复杂和最多样化的第二性特征是性梳子(SC)，这是一种在雄性果蝇亚门的前腿上排列的修饰刷毛。我们研究了六个代表性的非模式果蝇物种的SC形成，以努力理解梳状图案的变异是如何产生的。我们首先比较了两种具有相对较小梳子的物种的SC发育，一种是高氏果蝇，其SC保持大致横向，另一种是双足果蝇，相对于其他刷毛地标，两排SC牙齿旋转并向前移动。然后，我们分析了扩展的SCs与近端轴线平行的物种的梳状个体发育，包括无花果果蝇和单胞亚组的物种。我们的研究使我们能够确定在颧骨上产生纵向梳状突起的两种一般方法，我们发现一种单胞菌亚群物种(Drodexila Nikananu)的梳状突起在大小、方向和位置上与模式生物DroSingila Blackogaster相似，通过不同的发育机制形成其SC。我们还发现，腿部模式基因的蛋白质产物Dachshund(DAC)在所有物种的SC中都强烈减少，但在其他物种的刚毛中没有。我们的结果表明，成人SC位置的明显限制可能至少归因于两个不同的谱系特定的发育过程，尽管外力也可能起作用。
The most complex and diverse secondary sexual character in Drosophila is the sex comb (SC), an arrangement of modified bristles on the forelegs of a subclade of male fruit flies. We examined SC formation in six representative nonmodel fruit fly species, in an effort to understand how the variation in comb patterning arises. We first compared SC development in two species with relatively small combs, Drosophila takahashii, where the SCs remain approximately transverse, and Drosophila biarmipes, where two rows of SC teeth rotate and move in an anterior direction relative to other bristle landmarks. We then analyzed comb ontogeny in species with prominent extended SCs parallel to the proximodistal axis, including Drosophila ficusphila and species of the montium subgroup. Our study allowed us to identify two general methods of generating longitudinal combs on the tarsus, and we showed that a montium subgroup species (Drosophila nikananu) with a comb convergently similar in size, orientation and position to the model organism Drosophila melanogaster, forms its SC through a different developmental mechanism. We also found that the protein product of the leg patterning gene, dachshund (dac), is strongly reduced in the SC in all species, but not in other bristles. Our results suggest that an apparent constraint on SC position in the adult may be attributable to at least two different lineage-specific developmental processes, although external forces could also play a role.