Molecular Diversity

, 11:119

Evidence for positive Darwinian selection on the hepcidin gene of Perciform and Pleuronectiform fishes

Full Length Paper

DOI: 10.1007/s11030-007-9066-4

Cite this article as:
Padhi, A. & Verghese, B. Mol Divers (2007) 11: 119. doi:10.1007/s11030-007-9066-4

Abstract

Hepcidin is a small cysteine-rich peptide that plays an important role in antimicrobial activity and in maintaining iron homeostasis in vertebrates. Here we report on the underlying mechanism that maintains high sequence diversities among the hepcidin-like variants of perciform and pleuronectiform fishes. In contrast to mammals, maximum likelihood-based codon substitution analyses revealed that positive Darwinian selection (nonsynonymous to synonymous substitution, ω  > 1) is the likely cause of accelerated rate of amino acid substitutions in the hepcidin mature peptide region of these fishes. Comparison of models incorporating positive selection (ω  >  1) at certain sites with models not incorporating positive selection (ω <  1) failed to reject (p  =  0) the evidence of positive selection among the codon sites of percifom and pleuronectiform hepcidin. The adaptive evolution of this peptide in perciform and pleuronectiform fishes might be directed by pathogens when the host is exposed to new habitats/environments.

Keywords

HepcidinAntimicrobial peptidesFishPhylogenySubstitution ratesAdaptive evolution

Abbreviations

AMP

Antimicrobial peptide

ML

Maximum likelihood

BI

Bayesian inference

NJ

Neighbour joining

JTT

Jones-Taylor-Thornton

dN

Nonsynonymous nucleotide substitutions per nonsynonymous site

dS

Synonymous substitutions per synonymous site

ω

dN/dS

HKY

Hasegawa-Kishino-Yano

AIC

Akaike Information Criterion

hLR

Hierarchical likelihood ratio test

Γ

Invariable sites

γ

Gamma distribution shape parameter

Copyright information

© Springer Science+Business Media B.V. 2007

Authors and Affiliations

  1. 1.Department of Biological ScienceUniversity of TulsaTulsaUSA
  2. 2.Department of Biology, Mueller LabThe Pennsylvania State UniversityUniversity ParkUSA