Department of Population Genetics, National Institute of Genetics, Mishima, Shizuoka-ken, Japan.
PLoS One. 2011 Apr 25;6(4):e17295. doi: 10.1371/journal.pone.0017295.
Hsp70 genes may influence the expression of wing abnormalities in Drosophila melanogaster but their effects on variability in quantitative characters and developmental instability are unclear. In this study, we focused on one of the six Hsp70 genes, Hsp70Ba, and investigated its effects on within- and among-individual variability in orbital bristle number, sternopleural bristle number, wing size and wing shape under different environmental conditions. To do this, we studied a newly constructed deletion, Df(3R)ED5579, which encompasses Hsp70Ba and nine non-Hsp genes, in the heterozygous condition and another, Hsp70Ba(304), which deletes only Hsp70Ba, in the homozygous condition. We found no significant effect of both deletions on within-individual variation quantified by fluctuating asymmetry (FA) of morphological traits. On the other hand, the Hsp70Ba(304)/Hsp70Ba(304) genotype significantly increased among-individual variation quantified by coefficient of variation (CV) of bristle number and wing size in female, while the Df(3R)ED5579 heterozygote showed no significant effect. The expression level of Hsp70Ba in the deletion heterozygote was 6 to 20 times higher than in control homozygotes, suggesting that the overexpression of Hsp70Ba did not influence developmental stability or canalization significantly. These findings suggest that the absence of expression of Hsp70Ba increases CV of some morphological traits and that HSP70Ba may buffer against environmental perturbations on some quantitative traits.
Hsp70 基因可能会影响果蝇翅膀异常的表达，但它们对数量性状和发育不稳定性的变异性的影响尚不清楚。在这项研究中，我们专注于 6 个 Hsp70 基因之一的 Hsp70Ba，并研究了它在不同环境条件下对眶鬃毛数、胸侧鬃毛数、翅膀大小和翅膀形状的个体内和个体间变异性的影响。为此，我们研究了一种新构建的缺失，即包含 Hsp70Ba 和 9 个非 Hsp 基因的 Df(3R)ED5579 在杂合状态下和另一种缺失仅 Hsp70Ba 的 Hsp70Ba(304)在纯合状态下。我们发现这两种缺失对形态特征的波动不对称性（FA）量化的个体内变异性没有显著影响。另一方面，Hsp70Ba(304)/Hsp70Ba(304)基因型显著增加了雌性中以变异系数（CV）量化的鬃毛数和翅膀大小的个体间变异性，而 Df(3R)ED5579 杂合子则没有显著影响。缺失杂合子中 Hsp70Ba 的表达水平比对照纯合子高 6 到 20 倍，这表明 Hsp70Ba 的过表达对发育稳定性或定型没有显著影响。这些发现表明 Hsp70Ba 表达缺失会增加某些形态特征的 CV，并且 HSP70Ba 可能会缓冲某些数量性状对环境干扰的影响。
