2La chromosomal inversion enhances thermal tolerance of Anopheles gambiae larvae.
2La chromosomal inversion enhances thermal tolerance of Anopheles gambiae larvae.
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DOI：
10.1186/1475-2875-8-147
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发表时间：
2009-07-02
期刊：
影响因子：
3
通讯作者：
Besansky NJ
中科院分区：
文献类型：
--
作者：
Rocca KA;Gray EM;Costantini C;Besansky NJ
冈比亚按蚊广泛分布于撒哈拉以南非洲地区，这使其成为非洲大陆最有效的疟疾传播媒介。据推测，该物种的普遍存在源于反转多态性促进的局部适应。一种名为 2La 的逆温层与西非和中非的干旱地带密切相关：2La 固定在干旱稀树草原中，而 2L+a 排列主要出现在雨林中。承受高温暴露的能力是耐干旱性的重要组成部分，特别是在仅限于浅水坑的未成熟阶段。为了破译 2La 倒置在局部适应中的作用，目前的研究重点是两个仅在 2La 排列方面不同的种群中幼虫和蛹耐热性的变化。冈比亚 A. gambiae 的实验室菌落具有 2La 多态性，但具有所有其他已知倒位的标准，用于创建 2 个同核型群体（2L+a 和 2La）。然后在暴露于热应力（有或没有事先热硬化）后测试两个种群的第四龄幼虫和蛹的存活率。幼虫对 40°C 热应激的反应相同，约 50% 的幼虫在 1.5-2 小时后死亡，少数幼虫在 3 小时的应激后存活下来。当在热应激之前进行热硬化时，两个幼虫种群的耐热性均增加，2La 24 小时存活率显着超过 2L+a。蛹通常比幼虫更耐热，尽管 2La 蛹的耐热性低于 2L+a。热硬化对蛹的耐热性没有积极影响。热硬化后在 2La 幼虫中观察到的耐热性增加表明倒置核型的响应性（即热敏感性）更高。通过对热休克做出更剧烈的反应，2La 幼虫能够更好地抵抗干旱栖息地中可能致命的温度。与 2L+a 相比，2La 蛹的存活率较低可能反映了这种敏感性的代价，即热阻机制阻止了变态的成功完成。根据 2La 频率线两端的气候特征讨论了热阻的成本和效益。
The mosquito Anopheles gambiae is broadly distributed throughout sub-Saharan Africa and this contributes to making it the most efficient vector of malaria on the continent. The pervasiveness of this species is hypothesized to originate in local adaptations facilitated by inversion polymorphisms. One inversion, named 2La, is strongly associated with aridity clines in West and Central Africa: while 2La is fixed in arid savannas, the 2L+a arrangement is predominantly found in the rainforest. Ability to survive high temperature exposure is an essential component of aridity tolerance, particularly in immature stages that are restricted to shallow puddles. Toward deciphering the role of the 2La inversion in local adaptation, the present investigation focused on variation in larval and pupal thermo-tolerance in two populations dissimilar solely in 2La arrangement. A laboratory colony of A. gambiae that is polymorphic for 2La but standard for all other known inversions was used to create 2 homokaryotypic populations (2L+a and 2La). The survival of 4th instar larvae and pupae from both populations was then tested following exposure to thermal stress with and without prior heat hardening. Larvae responded identically to a 40°C heat stress, with about 50% of larvae dying after 1.5–2 h and few larvae surviving a 3 h stress. When heat hardened prior to the thermal stress, thermo-tolerance of both larval populations increased, with 2La 24 h survival significantly exceeding that of 2L+a. Pupae were generally more thermo-tolerant than larvae, although 2La pupae were less so than 2L+a. Heat hardening had no positive effect on pupal thermo-tolerance. The increased thermo-tolerance observed in 2La larvae following heat hardening suggests higher responsiveness (i.e., thermal sensitivity) of the inverted karyotype. By responding more drastically to the heat shock, 2La larvae are better equipped to resist the potentially lethal temperatures that occur in arid habitats. The lower survival of 2La pupae compared with 2L+a may reflect the cost of this sensitivity, whereby the thermal resistance mechanisms prevent successful completion of metamorphosis. The costs and benefits of thermal resistance are discussed in light of the climates characterizing either end of the 2La frequency cline.
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影响因子：
5.2
作者：
Dahlgaard, J;Loeschcke, V;Justesen, J
通讯作者：
Justesen, J
影响因子：
5.2
作者：
Feder, ME;Blair, N;Figueras, H
通讯作者：
Figueras, H
影响因子：
56.9
作者：
Huey, RB;Gilchrist, GW;Serra, L
通讯作者：
Serra, L
影响因子：
56.9
作者：
Coluzzi, M;Sabatini, A;Petrarca, V
通讯作者：
Petrarca, V
影响因子：
--
作者：
Simard F;Ayala D;Kamdem GC;Pombi M;Etouna J;Ose K;Fotsing JM;Fontenille D;Besansky NJ;Costantini C
通讯作者：
Costantini C