國立臺灣大學昆蟲學系暨研究所張慧羽2006-07-252018-06-292006-07-252018-06-292001http://ntur.lib.ntu.edu.tw//handle/246246/12558紅果蠅 (Drosophila albomicans) 日本 沖繩品系的雌蟲與輝顏果蠅 (D. nasuta ) 的 雄蟲雜交，第二子代呈現出偏雌的情況。 而這些果蠅品系本身均呈現正常的性比。 該偏雌的現象是由第一子代雄蟲造成，因 此推測日本沖繩紅果蠅的 3-X 染色體上帶 有性比偏差因子 (SR) 及其抑制因子，而輝 顏果蠅不具SR 也不具其抑制因子。又由 於台灣及泰國的紅果蠅品系與輝顏果蠅雜 交第二子代無性比偏差現象，故這些紅果 蠅品系可能不具SR。但是台灣及泰國的 紅果蠅和日本沖繩的紅果蠅交配並沒有偏 雌的現象，可見牠們雖然沒有SR 卻有SR 的抑制因子。 SR 及其抑制因子的互動關係有助於從 自私基因的觀點闡明本實驗室先前所提出 的 “紅果蠅階段性染色體進化模式” 中最 初造成癒合的 3-X 染色體頻率上升的作用 力。為了證實SR 確實與 3-X 染色體的頻 率上升有關，設計數個實驗族群，在不具 有抑制因子的情況下，比較帶與不帶SR 對3-X 染色體頻率上升的速率的影響。研 究結果顯示SR 可造成3-X 染色體頻率的 顯著上升。The F2 offspring from the cross between a female Drosophila albomicans from Okinawa and a male D. nasuta are female biased, whereas those strains have a normal 1:1 sex ratio themselves. The hybrid F1 male is the cause for sex ratio distortion. Therefore, we suggest that the 3-X chromosome of the Okinawa D. albomicans may contain both sex ratio distorter (SR) and its suppressor, but D. nasuta has neither. Taiwan and Thailand D. albomicans may not have SR because no sex ratio distortion was observed when crossed to D. nasuta . But they don’t show sex ratio distortion when crossed to Okinawa D. albomicans female either. This phenomenon suggests that although they don’t have SR, they have the suppressor of SR. The interaction between SR and its suppressor may elaborate the hypothesis “stepwise chromosome evolution of D. albomicans” for the selfish element SR on the 3-X chromosome can make an increase the frequency of the chromosome by meiotic drive. Several experimental populations were constructed to test the correlation between SR and the increase of 3-X. The result confirmed that the SR can indeed cause an increase of the frequency of 3-X chromosome.application/pdf32037 bytesapplication/pdfzh-TW國立臺灣大學昆蟲學系暨研究所染色體進化紅果蠅輝顏果蠅減數分裂驅動分離偏差因子性比偏差因子chromosomal evolutionDrosophila albomicansD. nasutameiotic drivesegregation distorter (SD)sex ratio distorter (SR)reporthttp://ntur.lib.ntu.edu.tw/bitstream/246246/12558/1/892313B002152.pdf