A CONSIDERATION OF THE NEGATIVE CORRELATION BETWEEN TRANSMISSION RATIO AND RECOMBINATION FREQUENCY IN A MALE RECOMBINATION SYSTEM OF DROSOPHILA MELANOGASTER
A CONSIDERATION OF THE NEGATIVE CORRELATION BETWEEN TRANSMISSION RATIO AND RECOMBINATION FREQUENCY IN A MALE RECOMBINATION SYSTEM OF DROSOPHILA MELANOGASTER
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果蝇雄性重组系统中传输率与重组频率负相关的考虑
DOI：
10.1266/jjg.53.13
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发表时间：
1978
期刊：
影响因子：
--
通讯作者：
Y. Hiraizumi
中科院分区：
文献类型：
--
作者：
K. Matthews;B. Slatko;D. W. Martin;Y. Hiraizumi
在T-007染色体Pr+区存在“主要”雄性重组元件(MR)的情况下，研究了与T-007相关的“次要”雄性重组元件与传播率(K)和雄性重组频率(θ)之间的负相关关系。这些数据表明，T-007染色体的臂上分布着许多次要的雄性重组元件。它们通常会导致k的减少和θ的增加，并且它们在每个品系内的雄性中的表达似乎是恒定的。更有趣的是，本观察也表明了另一种类型的雄性重组元件的存在。以前非男性重组第二染色体的Pr区(即MR+区)似乎发生了“MR相关突变”(类似于参数突变)。这种改变被称为MR‘，使携带该基因的染色体能够引起一些男性重组和扭曲的传播率。在这种情况下，MR‘的表达似乎在每个品系中的雄性之间有所不同。这表明，同一品系中的雄性之间的k和θ之间的关系与染色体中元素的位置有关。具体来说，位于染色体常染色质区域的次要元件在表达上似乎是“稳定的”，而位于中心异染色质或与之相邻的MR和MR‘元件似乎是“不稳定的”。这些元素的表达可能在每个品系内的雄性之间是不同的，因此一些雄性的MR或MR‘的活性较强(较低的k，较高的θ)，而对于其他雄性，它们的活性较弱(较高的k，较低的θ)。最后，估计“MR相关突变改变”，MR+→MR’的比率约为0.5。
The negative correlation between transmission ratio (k) and male recombination frequency (θ), which was found in the presence of the “major” male recombination element (Mr) in the pr+ region of the T-007 chromosome, was examined for hypothesized “minor” male recombination elements associated with T-007. The data indicate that many minor male recombination elements are distributed along the arms of the T-007 chromosome. They generally cause a reduction in k and an increase in θ, and their expression seems to be constant among males within each line.More interestingly, the presence of another type of male recombination element is also suggested by the present observations. It appears that a “Mr-related mutational change” (analogous to paramutation) occurs in the pr region (therefore, the Mr+ region) of previously non-male recombination second chromosomes. This change, designated Mr', enables those chromosomes which carry it to induce some male recombination and a distorted transmission ratio. In this case, the expression of Mr' seems to vary among males within each line.It is suggested that the relationship between k and θ among males within the same line is related to the position of the elements in the chromosome. Specifically, minor elements, which locate in largely euchromatic regions of the chromosome, appear to be “stable” in their expression, while the Mr and Mr' elements, which locate in or adjacent to the centric heterochromatin, appear to be “unstable”. The expression of these elements may be variable among males within each line such that the activities of Mr or Mr' are stronger (lower k, higher θ) for some males, while they are weaker (higher k, lower θ) for other males.Finally, it is estimated that the rate of the “Mr-related mutational change”, Mr+→Mr', is roughly 0.50.