Low Frequency Advantage in Mating of Drosophila pseudoobscura Karyotypes
Low Frequency Advantage in Mating of Drosophila pseudoobscura Karyotypes
复制标题
假暗果蝇核型交配的低频优势
作者：
E. Spiess
为了进一步探讨拟果蝇种群中第三染色体排列频率依赖性的证据和细节，设计了涉及箭头（Arrowhead）和派克峰（Pikes Peak）基因排列的多重选择交配实验，以测量在一种性别或两性中核型频率变化的相对交配倾向。在30 min的同核型无选择交配中，AR和PP各有10株杂交，交配速度最快（75%），交配速度最慢（20%）。将20对6日龄的F1杂交蝇不经醚化处理，置于小型有机玻璃室中观察30分钟。在交配试验的前一天，通过刺穿果蝇的翅膀来区分核型。每次都测试两种不同类型的两性，以衡量相对倾向，总交配频率和任何选型交配。(1)男性的AR/AR: PP/PP比值为2:18,4:16，间隔为1/10 ~ 18:2，相同核型的女性保持相等（10:10）；(2)(1)的倒数，即女性从2:18变为18:2，而男性保持10:10；(3)两性同时向同一方向变化；(4)异核型AR/PP与同核型AR/AR在相同核型的雄性中差异为2:18 ~ 18:2。
In order to substantiate evidence and explore further details of frequency dependency between third chromosome arrangements in Drosophila pseudoobscura populations, multiple-choice mating experiments involving karyotypes of Arrowhead (AR) and Pikes Peak (PP) gene arrangements were designed to measure relative mating propensity with frequencies of karyotypes varied in one sex or in both sexes. Ten strains each of AR and PP crossed inter se as in previous experiments contrast in being fastest (75% mated) and slowest (20%) mated, respectively, in homokaryotype no-choice matings of 30 min. duration. Twenty pairs of strain-cross F1 flies, 6 days old, were introduced unetherized into small Plexiglas chambers and observed for 30 min. Flies had been marked to distinguish karyotypes by puncturing a wing on the day before the mating tests. Two contrasting types of both sexes were tested each time to measure relative propensities, total mating frequency, and any assortative mating. Ratios of karyotypes and conditions were varied as follows: (1) AR/AR: PP/PP from 2:18, 4:16, by intervals of 1/10 to 18:2 among males while females of the same karyotypes were kept at equality (10:10); (2) the reciprocal of (1), namely, from 2:18 to 18:2 among females while males remained 10:10; (3) both sexes varied simultaneously in the same direction; and (4) heterokaryotype AR/PP versus homokaryotype AR/AR varied from 2:18 to 18:2 among males with females of the same karyotypes at equality.