Gametic frequency of second chromosomes of the T-007 type in a natural population of Drosophila melanogaster in Texas.
Gametic frequency of second chromosomes of the T-007 type in a natural population of Drosophila melanogaster in Texas.
复制标题
德克萨斯州黑腹果蝇自然群体中 T-007 型第二染色体的配子频率。
DOI：
10.1093/genetics/98.2.303
复制
发表时间：
1981
期刊：
影响因子：
3.3
通讯作者：
Gerstenberg,MV
中科院分区：
文献类型：
--
作者：
Hiraizumi,Y;Gerstenberg,MV
THET-007第二条染色体是1970年从德克萨斯州南部的一个自然种群黑腹果蝇中分离出来的，已知的是，在具有标准cn第二条染色体的雄性果蝇中，当使其杂合时，传播频率(K)为0.35-远远低于理论上预期的0.5。在德克萨斯州，这个物种的自然种群包含第二条染色体，与标准的bw遗传背景相反，与Thet-007染色体的扭曲传递频率相关联。为了解释这些染色体如何在自然种群中以非平凡的频率存在，有人推测，尽管当在实验室种群(如Ascn BW)的遗传背景下测试时，这些染色体显示出降低的k值，但在自然遗传背景下，它们平均可能显示大于0.5的k值。如果这是真的，在自然遗传背景下，Thet-007型染色体(T染色体)在男性配子中的频率应该高于女性配子。这项研究就是为了检验这一可能性。结果表明，这类染色体在雄性配子中的频率明显高于在雌性配子中的频率，并且在自然遗传背景下，这类染色体的传递频率高于0.5。这些结果表明，在德克萨斯州该物种的自然种群中，T染色体的行为类似于分离失调(SD)染色体。提出了ENT-007与SD染色体之间的可能关系。
TheT-007second chromosome, which was isolated from a natural population ofDrosophila melanogasterin south Texas in 1970, is known to show, when made heterozygous in males with a standardcn bwsecond chromosome, a transmission frequency (k) of 0.35—much lower than the theoretically expected 0.5. Natural populations of this species in Texas contain second chromosomes that, against the standardcn bwgenetic background, are associated with distorted transmission frequencies comparable to that of theT-007chromosome. In order to explain how such chromosomes can persist in natural populations in nontrivial frequencies, it has been postulated that, although such chromosomes show reducedkvalues when tested under the genetic background of a laboratory stock such ascn bw, they may show, on the average,kvalues larger than 0.5 under natural genetic backgrounds. If this were true, the frequency of chromosomes of theT-007type (Tchromosomes) should be higher in male than in female gametes under natural genetic backgrounds. The present study was conducted to examine this possibility. The results clearly showed that the frequency of such chromosomes was much higher among male than among female gametes, and that the transmission frequency of this type of chromosome was higher than 0.5 under natural genetic backgrounds. These results suggest thatTchromosomes behave like Segregation Distorter (SD) chromosomes in natural populations of this species in Texas. A possible relationship betweenT-007andSDchromosomes is suggested.