Open AccessPopulation genetic structure and a possible role for selection in driving phenotypic divergence in a rainbowfish ( Melanotaeniidae )
Author(s) -
YOUNG MICHAEL J.,
EVANS JONATHAN P.,
SIMMONS LEIGH W.
Publication year - 2011
Publication title -
biological journal of the linnean society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.906
H-Index - 112
eISSN - 1095-8312
pISSN - 0024-4066
DOI - 10.1111/j.1095-8312.2010.01558.x
Subject(s) - biology , divergence (linguistics) , genetic divergence , evolutionary biology , selection (genetic algorithm) , genetic algorithm , population , ecology , genetic structure , genetic variation , genetics , genetic diversity , gene , philosophy , linguistics , demography , artificial intelligence , sociology , computer science
Quantitative genetic divergence may be driven by drift or selection. The rainbowfish Melanotaenia australis exhibits phenotypic divergence among populations in Western Australia, although the mechanisms driving this divergence are unknown. We used microsatellites to assess neutral genetic divergence ( F ST ), and found a hierarchical pattern of subdivision consistent with low divergence between upstream and downstream populations (within drainages), moderate divergence between drainages (within regions), and high divergence between regions. Using a common‐garden approach, we measured quantitative genetic divergence in phenotypic traits ( Q ST ). By comparing this to expectations from neutral processes ( F ST ), we concluded that the effect of selection varies depending on the spatial scale considered. Within drainages, selection may be causing divergence between upstream and downstream phenotypes but, between regions, selection appears to homogenize phenotypes. This highlights the importance of spatial scale in studies of this kind, and suggests that, because variance in selection pressures can drive speciation, polymorphism in M. australis may represent speciation in action. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society , 2011, 102 , 144–160.