The three strains also differ importantly in regulation of gene expression when reared in common environments (Bougas et al. 2010).
Snout-vent length did not have a significant effect on the degree of melanism in juveniles reared in common garden (Table 3).
Significant differences between the two origins were maintained after three months of rearing in common environment but were less pronounced than at time of sampling in natural conditions.
Habitat-independent, genetically based intraspecific variation in brain architecture has also been found both in wild guppy (Poecilia reticulata) populations reared in common environments [ 11], and in laboratory lines of the medaka (Oryzias latipes; [ 10]).
In a comparison between genetically distinct resident and anadromous brook charr (Salvelinus fontinalis) reared in common conditions, Boulet et al. (2012) [ 37] observed that gene expression in the gills differed for 4% of the genes, a value comparable to what we observed after 3 months of common rearing.
Three F0 males and three F0 females, which were the offspring of wild West-Mediterranean D. labrax, were mated by artificial fertilization in a factorial cross to simultaneously produce eight families (one family was lost), which were reared in common garden conditions; the overall sex ratio in the F1 offspring was 43.8 % females.
They reared guppies in common gardens and found that introduced guppy populations rapidly lost their escape ability when introduced into low predation habitats.
In our study, environmental effects were minimized by rearing progenies in common garden conditions, indicating that the observed differences in sex-ratio are genetically based.
A low likelihood of detecting maternal effects in this case might have been due to collecting all adults from the same site and rearing offspring in common garden environments at unrestricted food levels (Marshall and Uller 2007; Allan et al. 2008).
It was instrumental in establishing an intellectual aristocracy whereby the nation could be sure of a cultural unity by entrusting government to scholars reared in a common tradition, nurtured in a common cultural heritage, and dedicated to common ideals of political and social life.
We thank John Loehr and three anonymous reviewers for helpful comments, Maarit Haataja, Ane Laugen, Katja Räsänen and Mattias Sterner for helping with the fieldwork, Jonas Andersson for assisting in the common garden experiment, and Heidi Kristanjankroon for measuring the degree of melanism in the frogs reared in the common garden.
