Diversity and selective pressures of anticoagulants in three medicinal leeches (Hirudinida: Hirudinidae, Macrobdellidae)

Ecology and Evolution

Sebastian Kvist²  Gi-Sik Min¹ 

[1] Department of Biological Sciences, Inha University, Nam-Gu, Korea;Museum of Comparative Zoology, Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, USA

关键词: Anticoagulant;    evolution;    FEL;    Hirudinida;    medicinal leeches;    PARRIS;    REL;    selection pressures;    SLAC;   

DOI  :  10.1002/ece3.480

来源: Wiley

【 摘 要 】

Abstract

Although medicinal leeches have long been used as treatment for various ailments because of their potent anticoagulation factors, neither the full diversity of salivary components that inhibit coagulation, nor the evolutionary selection acting on them has been thoroughly investigated. Here, we constructed expressed sequence tag libraries from salivary glands of two species of medicinal hirudinoid leeches, Hirudo verbana and Aliolimnatis fenestrata, and identified anticoagulant-orthologs through BLASTx searches. The data set then was augmented by the addition of a previously constructed EST library from the macrobdelloid leech Macrobdella decora. The identified orthologs then were compared and contrasted with well-characterized anticoagulants from a variety of leeches with different feeding habits, including non-sanguivorous species. Moreover, four different statistical methods for predicting signatures of positive and negative evolutionary pressures were used for 10 rounds each to assess the level and type of selection acting on the molecules as a whole and on specific sites. In total, sequences showing putative BLASTx-orthology with five and three anticoagulant-families were recovered in the A. fenestrata and H. verbana EST libraries respectively. Selection pressure analyses predicted high levels of purifying selection across the anticoagulant diversity, although a few isolated sites showed signatures of positive selection. This study represents a first attempt at mapping the anticoagulant repertoires in a comparative fashion across several leech families.

【 授权许可】

CC BY   
© 2013 The Authors. Ecology and Evolution published by Blackwell Publishing Ltd.

Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.