Directional selection and developmental stability: evidence from fluctuating asymmetry of dental characters in mice
Directional selection and developmental stability: evidence from fluctuating asymmetry of dental characters in mice
复制标题
方向选择和发育稳定性：小鼠牙齿特征波动不对称性的证据
作者：
L. Leamy
在经过11代选择的小鼠系中，对上颌第一磨牙（m1）宽度的增加（上线）和减少（下线）进行了发育稳定性评估，主要是为了验证这种稳定性会随着时间的推移而随着选择而下降的假设。波动性不对称（FA）被用作发育稳定性的逆测量，并计算了每代m1和相关性状，下颌第二磨牙（m2）。经世代间FA回归测定，只有m2下选系的稳定性下降具有统计学意义，而这一趋势与对照系没有显著差异。然而，对所有三个系进行合并得到的联合回归在两个磨牙中都明显不同于零，这被认为是由于选择实验期间近亲繁殖可能产生的纯合性增加而导致稳定性下降的证据。两个磨牙选择系的FA代际变异均大于对照系，特别是m2。m1（和m2）遗传力较高，但两磨牙FA的加性遗传变异均不显著。
Developmental stability was assessed among lines of mice subjected to 11 generations of selection for increased (up line) and decreased (down line) widths of the first maxillary molar (M 1), primarily to test the hypothesis that this stability would decline over time as a result of selection. Fluctuating asymmetry (FA) was used as an inverse measure of developmental stability, and was calculated for the M 1 and a correlated character, the second mandibular molar (M 2), in each generation. As measured by the regression of FA on generations, there was a statistically significant decline in stability only in the down selection line for the M 2, and this trend did not differ significantly from that for the control line. The combined regressions obtained from pooling over all three lines were significantly different from zero in both molars, however, and this was taken to be evidence of a decline in stability due to increased homozygosity presumably generated by inbreeding during the selection experiment. The variation in FA among generations was greater for the selection lines than the control line for both molars, especially for the M 2. The heritability of the M 1 (and M 2) was high, but there was no significant additive genetic variance for FA in either molar.