《自然》：一种特殊基因可在蚊子中大量扩散

Stemcell海洋

英国《自然》网站刊登一项最新研究发现，一种特殊基因可以在蚊子种群中大量扩散，这将大大推动用转基因蚊子防治疟疾的研究进展。* D0 R9 T" _7 X
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在用转基因蚊子防治疟疾方面，过去已有研究发现了一些能够减少蚊子传播疟疾能力的特殊基因，但问题是，如果这些基因不能在野外的蚊子种群中迅速扩散，即使在环境中投放一些转基因蚊子，也不会起到太大的作用。7 m3 _" N$ o$ `/ f$ R

, v- C% \4 I( t- _英国帝国理工学院的研究人员及其国际同行报告说，他们找到了一个有助于解决这个问题的基因，该基因会指导合成一种名为I-SceI的酶，而这种酶会在蚊子的繁殖过程中发挥作用，其结果是雄性蚊子的所有精子中都会含有这种酶，将这种基因传给下一代，并会代代相传。
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0 K7 B# Q, K9 m+ Z3 v6 i研究人员向实验室培养的蚊子群体中投放少量含有该基因的蚊子，结果经过12代蚊子的繁殖，也就是几个月的时间，整个蚊子群体中就有一半都携带这种基因。9 s* p9 y8 E; [

' n! v7 Z5 V4 |' c9 o/ @/ f9 K% D因此，如果能将减少蚊子传播疟疾能力的基因与这个基因绑定到一起，再将这种转基因蚊子投放到环境中，其防治疟疾的效果必定会大大增强。（来源：新华网 黄堃）
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延伸阅读：A synthetic homing endonuclease-based gene drive system in the human malaria mosquito: v+ |2 f+ L9 ~
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摘要：Genetic methods of manipulating or eradicating disease vector populations have long been discussed as an attractive alternative to existing control measures because of their potential advantages in terms of effectiveness and species specificity1, 2, 3. The development of genetically engineered malaria-resistant mosquitoes has shown, as a proof of principle, the possibility of targeting the mosquito’s ability to serve as a disease vector4, 5, 6, 7. The translation of these achievements into control measures requires an effective technology to spread a genetic modification from laboratory mosquitoes to field populations8. We have suggested previously that homing endonuclease genes (HEGs), a class of simple selfish genetic elements, could be exploited for this purpose9. Here we demonstrate that a synthetic genetic element, consisting of mosquito regulatory regions10 and the homing endonuclease gene I-SceI11, 12, 13, can substantially increase its transmission to the progeny in transgenic mosquitoes of the human malaria vector Anopheles gambiae. We show that the I-SceI element is able to invade receptive mosquito cage populations rapidly, validating mathematical models for the transmission dynamics of HEGs. Molecular analyses confirm that expression of I-SceI in the male germline induces high rates of site-specific chromosomal cleavage and gene conversion, which results in the gain of the I-SceI gene, and underlies the observed genetic drive. These findings demonstrate a new mechanism by which genetic control measures can be implemented. Our results also show in principle how sequence-specific genetic drive elements like HEGs could be used to take the step from the genetic engineering of individuals to the genetic engineering of populations.
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