A study of the genetic basis of the sexual dimorphism for wing length in Drosophila melanogaster.
A study of the genetic basis of the sexual dimorphism for wing length in Drosophila melanogaster.
复制标题
果蝇翅长性别二态性遗传基础的研究。
作者：
Margaret A. Bird;Henry E. Schaffer
采用双向定向选择法对果蝇雌雄翅长差异的增减进行了研究，探讨了果蝇性二态数量性状的遗传基础。性别二型（SD），定义为家庭内性别之间的平均翅长差异，提供了选择的标准。这两个线（高SD，低SD）迅速分歧，在15代的选择，表明存在广泛的遗传变异的基因型-性别相互作用的基础上观察到的性二型。有证据表明，当选择放松时，两个品系的遗传变异性都持续存在。经过10代的自由选择后，两个品系之间的大部分分歧仍然存在。在高线的性别二型性水平的变化主要是由于男性翅长的减少;在低线的SD的变化大部分是女性翅长减少的结果。两个品系中的两种性别的翅长的总体减少被解释为近亲繁殖的影响。利用标记倒位技术，通过选择系间的染色体置换，研究了两个选择系SD特征的遗传控制的分布和性质。这两条线不同的因素位于三个主要染色体对。染色体III对品系间SD水平差异的影响最大，并且当存在于纯合与杂合组合中时显示出总体加性效应。染色体II的影响最小，与显着的显性效应的高II是明显的杂合子与纯合子相比。X染色体的影响是中等的。有一些证据表明，非同源染色体之间的相互作用。
The genetic basis of a sexually dimorphic quantitative character in Drosophila melanogaster was investigated by means of two-way directional selection for increased and decreased differences between male and female wing length. The sex dimorphism (SD), defined as the mean wing length difference between the sexes, within families, provided the criterion for selection.-The two lines (High SD, Low SD) diverged rapidly during the 15 generations of selection, indicating the presence of extensive genetic variability for the genotype-sex interaction underlying the observed sexual dimorphism. There was evidence that genetic variability persisted in both lines when selection was relaxed. Most of the divergence between the two lines remained after 10 generations of relaxed selection.-The change in the level of sex dimorphism in the High line was due primarily to a decrease in male wing length; in the Low line most of the change in SD was the result of a decrease in female wing length. An overall reduction in wing length in both sexes in both lines is interpreted as an effect of inbreeding.-The distribution and nature of the genetic control underlying the SD characteristic of the two selection lines was investigated by chromosome substitution between selection lines using a marked inversion technique. The two lines differed by factors located on each of the three major chromosome pairs. Chromosome III had the greatest effect on the difference in SD level between lines, and showed an overall additive effect when present in homozygous versus heterozygous combination. Chromosome II had the least effect, with a significant dominance effect of the High II being evident when heterozygotes were compared with homozygotes. The effect of the X chromosome was intermediate. There was some evidence of interaction between non-homologous chromosomes.