Data from: Sexual antagonism for resistance and tolerance to infection in Drosophila melanogaster

A critical task in evolutionary genetics is to explain the persistence of heritable variation in fitness-related traits such as immunity. Ecological factors can maintain genetic variation in immunity, but less is known about how other factors, such as antagonistic pleiotropy, influence variation in immunity. Sexually dimorphic immunity – with females often being more immune-competent – may maintain variation in immunity in dioecious populations. Most eco-immunological studies assess host resistance to parasites, rather than the host's ability to maintain fitness during infection (tolerance). Distinguishing between resistance and tolerance is important as they are thought to have markedly different evolutionary and epidemiological outcomes. Few studies have investigated tolerance in animals and the extent of sexual dimorphism in tolerance is unknown. Using males and females from 50 Drosophila melanogaster genotypes, we investigated possible sources of genetic variation for immunity by assessing both resistance and tolerance to the common bacterial pathogen Pseudomonas aeruginosa. We found evidence of sexual dimorphism and sexual antagonism for both traits, and a trade-off between resistance and tolerance. Our findings suggest that antagonistic pleiotropy may be a major contributor to variation in immunity, with implications for host-parasite coevolution.进化遗传学的一项核心任务是阐释免疫等与适合度相关性状的可遗传变异维持机制。生态因子可维持免疫相关的遗传变异，但对于拮抗多效性（antagonistic pleiotropy）等其他因素如何影响免疫性状变异的认知仍较为有限。免疫性状的性二态性（sexually dimorphic immunity）——通常雌性的免疫活性更强——或可维持雌雄异体种群中免疫性状的遗传变异。多数生态免疫学研究多聚焦于宿主对寄生虫的抗性（resistance），而非宿主在感染过程中维持适合度的能力，即耐受（tolerance）。区分抗性与耐受至关重要，因为二者被认为具有显著不同的进化与流行病学效应。目前针对动物耐受性状的研究较少，且耐受性状的性二态程度尚不明确。本研究以50个黑腹果蝇（Drosophila melanogaster）基因型的雌雄个体为实验材料，通过评估宿主对常见细菌性病原菌铜绿假单胞菌（Pseudomonas aeruginosa）的抗性与耐受能力，探究了免疫性状遗传变异的潜在来源。研究结果显示，这两种免疫性状均存在性二态性与性拮抗效应，且抗性与耐受之间存在进化权衡。本研究结果表明，拮抗多效性可能是免疫性状变异的主要驱动因素，这对宿主-寄生虫协同进化研究具有重要理论启示。