To what extent evolutionary inference can be based on phenotypes? A pretty fundamental question in the field of evolutionary biology, and particularly when dealing with the hypothesis of evolutionary responses to e.g. harvesting or climate change. The recent synthesis paper
Naish KA, Hard JJ (2008) Bridging the genotype and the phenotype: linking genetic variation, selection and adaptation in fishes. Fish and Fisheries 9:396-422
investigates/summarizes genetic methods through which the analyses of phenotypic shifts in fish stocks could be strengthened and their mechanisms could be better understood. The paper is in general very informative and reviews vast amount of relevant literature. The major conclusion of the authors is that rigorous interactions between the fields of quantitative and molecular genetics would provide new insights into evolutionary processes in wild population and, in general, this approach can be seen as the “future direction” in such analyses. To this end, however, both methodology and statistical tools should be improved and become more commonly available. Similarly, estimates of selection acting on fitness related phenotypic traits as well as covariance between the traits would be urgently needed.