Genetic exchange in 2La inversion heterokaryotypes of Anopheles gambiae.
Genetic exchange in 2La inversion heterokaryotypes of Anopheles gambiae.
复制标题
冈比亚按蚊2La反转异核型的遗传交换。
DOI：
10.1111/j.1365-2583.2007.00764.x
复制
发表时间：
2007
影响因子：
2.6
通讯作者：
Besansky,NJ
中科院分区：
文献类型：
--
作者：
Stump,AD;Pombi,M;Goeddel,L;Ribeiro,JMC;Wilder,JA;dellaTorre,A;Besansky,NJ
在疟疾媒介冈比亚按蚊（Anopheles gambiae）中，2号染色体的交替排列（2La和2L+a）沿沿着干旱梯度的相对频率不同，这表明自然选择对倒位内的目标的作用。我们检测这些目标的长期目标部分取决于安排之间的基因交换水平。因此，我们估计了2L上的重组率从回交后代的2La/+aheterokaryotypes和作为对照，从2L+ ahhomokaryotypes。在同核型中，重组率是均匀的，约为2.0厘摩/兆碱基（cM/Mb）。在异核型中，重排区域内的重组减少到< 0.5 cM/Mb，重排两侧的重组水平略高但仍然降低（< 1.0 cM/Mb）。然而，几乎所有的标记，包括那些非常接近远端倒位断点之间的基因交换记录。这些结果表明，减少重组是一个必要的，但不是充分的机制，为遗传隔离之间的替代安排，并针对不同的染色体背景，可以确定的目标，自然选择。
In the malaria vectorAnopheles gambiae, alternative arrangements of chromosome 2 (2La and 2L+a) vary in relative frequency along clines of aridity, suggesting the action of natural selection on targets within the inversion. Our long term goal of detecting such targets depends in part on the level of genetic exchange between arrangements. Accordingly, we estimated recombination rates on 2L from the backcross progeny of 2La/+aheterokaryotypes and as a control, from 2L+ahomokaryotypes. In homokaryotypes, the recombination rate was uniform at ~2.0 centimorgans per megabase (cM/Mb). In heterokaryotypes, recombination within the rearranged region was reduced to < 0.5 cM/Mb, with slightly higher but nevertheless reduced levels (< 1.0 cM/Mb) flanking the rearrangement. Yet, gene exchange was recorded between nearly all markers, including those very near the distal inversion breakpoint. These results suggest that reduced recombination is a necessary but not sufficient mechanism for genetic isolation between alternative arrangements, and that the targets of natural selection can be identified against the different chromosomal backgrounds.