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Demise of Marimermithida refines primary routes of transition to parasitism in roundworms

Authors :
Alexei V. Tchesunov
Olga V. Nikolaeva
Leonid Yu. Rusin
Nadezda P. Sanamyan
Elena G. Panina
Dmitry M. Miljutin
Daria I. Gorelysheva
Anna N. Pegova
Maria R. Khromova
Maria V. Mardashova
Kirill V. Mikhailov
Vladimir V. Yushin
Nikolai B. Petrov
Vassily A. Lyubetsky
Mikhail A. Nikitin
Vladimir V. Aleoshin
Publication Year :
2022
Publisher :
Cold Spring Harbor Laboratory, 2022.

Abstract

Nematodes (roundworms) are ubiquitous animals commonly dominating in ecological communities and networks, with many parasites and pathogen vectors of great economic and medical significance. Nematode parasites are remarkably diverse in life strategies and adaptations at a great range of hosts and dimension scales, from whales to protozoan cells. Their life history is intricate and requires understanding to study the genomic, structural and ecological bases of successful transitions to parasitism. Based on analyses of rDNA for a representative sampling of host-associated and free-living groups, we dismiss the last higher-rank nematode taxon uniting solely parasitic forms (Marimermithida) and show that primarily marine parasitism emerged independently and repeatedly within only few free-living lineages. We re-evaluate the significance of some traditionally important phenotypic characters and report the phenomenon of dramatic adaptation to parasitism on very short evolutionary timescales. A cross-phylum character interpretation vindicates that non-intestinal (in-tissue or cavitary) host capture was likely a primary route of transition to truly exploitive parasitism (vs. intestinal commensalism) in roundworms, and extant nematode parasitoids (larval parasites) infesting the host body cavity or internal organs realise this primary lifestyle. Parasitism may have evolved in nematodes as part of innate pre-adaptations to crossing environmental boarders, and such transitions have been accomplished multiple times successfully in the phylum history.

Details

Database :
OpenAIRE
Accession number :
edsair.doi...........0bc7eb03d12b55db2f1fd44e2eaa0f5d
Full Text :
https://doi.org/10.1101/2022.02.15.480519