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Figure 7 | EvoDevo

Figure 7

From: Posterior localization of ApVas1 positions the preformed germ plasm in the sexual oviparous pea aphid Acyrthosiphon pisum

Figure 7

Phylogenetic distribution of mechanisms for germline specification within the Paraneoptera. In the phylogenetic tree we display four orders of the superorder Paraneoptera: Psocoptera (booklice, barklice), Phthiraptera (trulice), Thysanoptera (thrips), and Hemiptera (true bugs). For discussing germline specification within the Hemiptera, we present four suborders including Sternorrhyncha (aphids, whiteflies, scales), Auchenorrhyncha (cicadas, leafhoppers), Coleorrhyncha (moss bugs), and Heteroptera (true bugs). Squares A, B, and C designate mechanisms of germline specification: A, germ cells are derived from the mesoderm during mid/late embryogenesis; B, germ cells are segregated adjacent to the posterior blastoderm, which takes place after formation of the blastoderm, but a preformed germ plasm has not been identified; C, germline specification is driven by a preformed germ plasm located in the posterior pole (Drosophila) or slightly anterior to the posterior end (aphid) of the egg. With the exceptions of booklice (Liposcelis divergens; B) [62], thrips (Haplothrips verbasci; C) [63], and scale insects (Pseudococcus mcdanieli, Lecanodiaspis pruinosa, and Icerya purchase; B) [39], where study of germline segregation was carried out with traditional microscopic approaches, mechanisms of germline specification are deduced from expression data or functional analysis of the germline marker vas/Vas. Sources for molecular data: Hemiptera: aphids (Acyrthosiphon pisum; C) [14], true bugs (Oncopeltus fasciatus; B) [36, 64]; other Hemimetabola: crickets (Gryllus bimaculatus; A) [35]; Holometabola: honeybees (Apis mellifera; A) [32], the flour beetle (Tribolium castaneum; B) [34], fruit flies (Drosophila melanogaster; C) [53]. Phylogenetic relationships of the Paraneoptera are based upon Grimaldi and Engel [65]; monophyletic clades within the Hemiptera are from Wheeler et al.[66] and Cryan and Urban [67]. Abbreviation: PGCs, primordial germ cells.

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