No apparent cost of evolved immune response in Drosophila melanogaster
No apparent cost of evolved immune response in Drosophila melanogaster
复制标题
DOI：
10.1111/evo.12896
复制
发表时间：
2016-04-01
期刊：
影响因子：
3.3
通讯作者：
Prasad, Nagaraj G.
中科院分区：
文献类型：
--
作者：
Gupta, Vanika;Venkatesan, Saudamini;Prasad, Nagaraj G.
免疫系统的维护和部署是昂贵的，因此预计将与其他需要资源的特征进行权衡，如繁殖。我们用实验室实验进化的方法对这个由来已久的想法进行了测试。在本研究中，对黑腹果蝇复制种群进行了三种选择方案：I(感染昆虫假单胞菌)、S(假感染硫酸镁)和U(未经处理的对照)。经过30代的筛选，与U区和S区的果蝇相比，I区的果蝇在感染昆虫病原虫后进化出更好的存活率。然而，与预期和之前的报告相反，我们没有发现任何证据表明免疫力和其他与生活史相关的特征之间存在权衡，如寿命、繁殖力、鸡蛋孵化率或发育时间。经过45代的选择，对一组群体的选择变得宽松。即使在15代之后，在宽松选择制度下的种群感染后的存活率也没有下降。我们推测，要么进化的免疫反应的成本可以忽略不计，要么我们在研究中没有研究的生殖行为或其他免疫机制等特征发生了权衡。我们的研究表明，至少在某些条件下，生活史的权衡可能在维持免疫力的变化方面起不到什么作用。
Maintenance and deployment of the immune system are costly and are hence predicted to trade-off with other resource-demanding traits, such as reproduction. We subjected this longstanding idea to test using laboratory experimental evolution approach. In the present study, replicate populations of Drosophila melanogaster were subjected to three selection regimesI (Infection with Pseudomonas entomophila), S (Sham-infection with MgSO4), and U (Unhandled Control). After 30 generations of selection flies from the I regime had evolved better survivorship upon infection with P. entomophila compared to flies from U and S regimes. However, contrary to expectations and previous reports, we did not find any evidence of trade-offs between immunity and other life history related traits, such as longevity, fecundity, egg hatchability, or development time. After 45 generations of selection, the selection was relaxed for a set of populations. Even after 15 generations, the postinfection survivorship of populations under relaxed selection regime did not decline. We speculate that either there is a negligible cost to the evolved immune response or that trade-offs occur on traits such as reproductive behavior or other immune mechanisms that we have not investigated in this study. Our research suggests that at least under certain conditions, life-history trade-offs might play little role in maintaining variation in immunity.