Carlson, S.M. & Seamons, T.R. 2008. A review of quantitative genetic components of fitness in salmonids: implications for adaptation to future change. Evolutionary Applications 1(2): 222–238 doi:10.1111/j.1752-4571.2008.00025.x
This review sums up an impressive amount of data from quantitative genetic studies of Salmonid fishes. The aims of this review were to summarise the published heritability and genetic correlation estimates and to find out whether there are differences in the estimates among categorical variables (e.g. species, traits). More specific goals of the review include finding out if it is feasible to make generalisations about heritabilities of traits across groups, e.g. taxa or populations, as well as finding out whether estimates obtained from one environment (e.g. hatchery) can be used to make inferences about the situation in another environment (e.g. wild).
Although a large number of heritability estimates (2049) are used, the analyses suffer from the data being biased – a small number of species, age groups, rearing conditions and types of trait account for the majority of estimates. For instance, data on wild populations and behavioural traits were nearly absent. This makes drawing any conclusions very difficult. Despite the complexity of data, a few conlcusions are made anyway. Overall, heritabilities are biased towards low values (median 0.22), while genetic correlations are biased towards high values (median 0.4). The results also confirm what has been found in earlier reviews that life history traits appear to have lower heritabilities than morphological traits, while genetic correlations show the opposite trend.
It is a bit surprising that no meta-analytical approach was used, which could take into account the precision of the estimates (although it is mentioned that 40% of the studies did not report error estimates). Also, it would have been nice to see whether different methods and models for estimation of the parameters would have shown any effect, in the analyses presented, the median value was used, if heritabilites were calculated with more than one method. However, all the raw data is provided in the extensive supplementary material, if anyone is keen to do some data mining of their own.
