Blood parasites shape extreme major histocompatibility complex diversity in a migratory passerine
Blood parasites shape extreme major histocompatibility complex diversity in a migratory passerine
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DOI：
10.1111/mec.14592
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发表时间：
2018-06-01
影响因子：
4.9
通讯作者：
Radwan, Jacek
中科院分区：
文献类型：
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作者：
Biedrzycka, Aleksandra;Bielanski, Wojciech;Radwan, Jacek
病原体是驱动脊椎动物主要组织相容性复合体（MHC）高度多态性基因进化和维持的主要力量之一。虽然MHC蛋白在病原体识别中至关重要，但病原体介导的选择如何促进和维持MHC多样性，特别是在具有高度重复的MHC基因的宿主物种中，仍然知之甚少。芦苇莺（Acrocephalus schoenobaenus）具有高度重复的MHC基因，利用高通量MHC基因分型的数据，我们能够调查禽疟疾寄生虫在多大程度上解释了长期研究人群中MHC I类超型的时间波动。我们调查了两种不同菌株的血变形杆菌的感染状况和感染强度，这是禽疟疾寄生虫，已知有显着的健身后果，在莎草莺。我们发现，在特定的MHC I类超型携带者中，禽疟疾的患病率是其频率变化的一个重要预测因素。这一发现表明，禽疟感染部分驱动的时间波动的MHC I类超型。此外，我们发现具有大量不同超型的个体对禽疟具有更高的抵抗力，但没有证据表明最佳的MHC I类多样性。因此，两种研究的疟原虫株似乎选择高MHC I类超型多样性。这样的选择可以解释的维护非常高的数量的MHC I类基因拷贝在莎草莺，也可能在其他雀，其中禽疟疾是一种常见的疾病。
Pathogens are one of the main forces driving the evolution and maintenance of the highly polymorphic genes of the vertebrate major histocompatibility complex (MHC). Although MHC proteins are crucial in pathogen recognition, it is still poorly understood how pathogen-mediated selection promotes and maintains MHC diversity, and especially so in host species with highly duplicated MHC genes. Sedge warblers (Acrocephalus schoenobaenus) have highly duplicated MHC genes, and using data from high-throughput MHC genotyping, we were able to investigate to what extent avian malaria parasites explain temporal MHC class I supertype fluctuations in a long-term study population. We investigated infection status and infection intensities of two different strains of Haemoproteus, that is avian malaria parasites that are known to have significant fitness consequences in sedge warblers. We found that prevalence of avian malaria in carriers of specific MHC class I supertypes was a significant predictor of their frequency changes between years. This finding suggests that avian malaria infections partly drive the temporal fluctuations of the MHC class I supertypes. Furthermore, we found that individuals with a large number of different supertypes had higher resistance to avian malaria, but there was no evidence for an optimal MHC class I diversity. Thus, the two studied malaria parasite strains appear to select for a high MHC class I supertype diversity. Such selection may explain the maintenance of the extremely high number of MHC class I gene copies in sedge warblers and possibly also in other passerines where avian malaria is a common disease.