Evolution of reproductive mode variation and host associations in a sexual-asexual complex of aphid parasitoids.
Evolution of reproductive mode variation and host associations in a sexual-asexual complex of aphid parasitoids.
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DOI：
10.1186/1471-2148-11-348
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发表时间：
2011-12-01
影响因子：
3.4
通讯作者：
Vorburger C
中科院分区：
文献类型：
--
作者：
Sandrock C;Schirrmeister BE;Vorburger C
fabarum Lysiphlebus group是一个分类不明确的拟寄生物蚜虫复合体，目前分为三个已描述的物种，包括有性（雌雄同体）和无性（雌雄同体）谱系，关系不明。具体来说，在这个系统中，无性动物是如何从有性动物进化而来的，生殖模式在多大程度上仍然通过遗传交换联系在一起，这个复杂的结构在多大程度上是由地理或宿主相关的分化构成的，以及物种名称是否有效，这些都尚不清楚。结合种群遗传和系统发育方法，我们在来自欧洲各地的拟寄生蜂的综合样本中解决了这些问题。蚕豆菇类群寄生蜂以无性繁殖为主，无性种群表现出较高的基因型多样性。有性种群只在法国南部常见；在其他地方，有性繁殖仅限于特定的蚜虫宿主。虽然生殖方式在线粒体谱系上聚集，在核微卫星位点上有显著的分化，但有明确的证据表明，遗传交换，特别是在被有性和无性寄生蜂攻击的宿主上。微卫星数据进一步显示，部分寄主蚜虫的寄生蜂分化明显，但整个蚕豆蚜类群的线粒体序列变异不超过1.32%，且呈现很浅的拓扑结构。用于描述物种的形态学特征发现在系统发育上是非保守的。我们的研究结果表明，有性-无性的蚕豆乳杆菌群代表了一个生殖模式之间不完全隔离的年轻谱系复合体。我们提出了三种遗传交换机制，可以共同解释在无性拟寄生物中观察到的高基因型多样性：(i)通过“传染性孤雌生殖”形成新的无性谱系，（ii）通过有性谱系与有性系雌性交配的渗入，以及（iii）无性谱系中的“隐性性”，由已知的有性系自发产生的罕见雄性介导。从不同蚜虫采集的寄生蜂之间的部分强分化表明寄主专门化在这些寄生蜂中很容易进化。最后，我们得出结论，根据我们的资料，目前的分类划分为三种的豆科植物是不成立的。
The Lysiphlebus fabarum group is a taxonomically poorly resolved complex of aphid parasitoids, presently split into three described species that comprise sexual (arrhenotokous) and asexual (thelytokous) lineages of unknown relationship. Specifically, it is unclear how asexuals evolved from sexuals in this system, to what extent reproductive modes are still connected by genetic exchange, how much the complex is structured by geography or by host-associated differentiation, and whether species designations are valid. Using a combination of population genetic and phylogenetic approaches, we addressed these issues in a comprehensive sample of parasitoid wasps from across Europe. Asexual reproduction predominated in parasitoids of the L. fabarum group, with asexual populations exhibiting high genotypic diversity. Sexual populations were only common in southern France; elsewhere sexual reproduction was restricted to specific aphid hosts. Although reproductive modes were aggregated on the mitochondrial genealogy and significantly differentiated at nuclear microsatellite loci, there was clear evidence for genetic exchange, especially on hosts attacked by sexual and asexual parasitoids. The microsatellite data further revealed that parasitoids collected from certain host aphids were significantly differentiated, yet the mitochondrial sequence variation across the entire L. fabarum group did not exceed 1.32% and exhibited a very shallow topology. Morphological characters used for delineation of described species were found to be phylogenetically non-conservative. Our results suggest that the sexual-asexual L. fabarum group represents a young complex of lineages with incomplete isolation between reproductive modes. We propose three mechanisms of genetic exchange that may jointly explain the high genotypic diversity observed in asexual parasitoids: (i) the formation of new asexual lineages via 'contagious parthenogenesis', (ii) introgression from sexual lineages through matings between sexual males and thelytokous females, and (iii) 'cryptic sex' within asexuals, mediated by rare males that thelytokous lines are known to produce spontaneously. The partially strong differentiation among wasps collected from different aphids suggests that host specialization can evolve readily in these parasitoids. Finally, we conclude that in the light of our data, the current taxonomic division of the L. fabarum group into three species cannot be upheld.
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影响因子：
3.3
作者：
Belshaw, R;Quicke, DLJ;Godfray, HCJ
通讯作者：
Godfray, HCJ
影响因子：
4.9
作者：
Clement, M;Posada, D;Crandall, KA
通讯作者：
Crandall, KA
影响因子：
1.9
作者：
Daza-Bustamante, P;Fuentes-Contreras, E;Niemeyer, HM
通讯作者：
Niemeyer, HM
影响因子：
4.9
作者：
Barrett, Luke G.;Thrall, Peter H.;Linde, Celeste C.
通讯作者：
Linde, Celeste C.
DOI：
10.1111/j.1471-8286.2006.01522.x
发表时间：
2007-01-01
期刊：
MOLECULAR ECOLOGY NOTES
影响因子：
--
作者：
Arnaud-Haond, Sophie;Belkhir, Khalid
通讯作者：
Belkhir, Khalid