title: Heritability and evolvability of fitness and nonfitness traits: Lessons from livestock.
abstract: Data from natural populations have suggested a disconnection between trait heritability (variance standardized additive genetic variance, VA ) and evolvability (mean standardized VA ) and emphasized the importance of environmental variation as a determinant of trait heritability but not evolvability. However, these inferences are based on heterogeneous and often small datasets across species from different environments. We surveyed the relationship between evolvability and heritability in >100 traits in farmed cattle, taking advantage of large sample sizes and consistent genetic approaches. Heritability and evolvability estimates were positively correlated (r = 0.37/0.54 on untransformed/log scales) reflecting a substantial impact of VA on both measures. Furthermore, heritabilities and residual variances were uncorrelated. The differences between this and previously described patterns may reflect lower environmental variation experienced in farmed systems, but also low and heterogeneous quality of data from natural populations. Similar to studies on wild populations, heritabilities for life-history and behavioral traits were lower than for other traits. Traits having extremely low heritabilities and evolvabilities (17% of the studied traits) were almost exclusively life-history or behavioral traits, suggesting that evolutionary constraints stemming from lack of genetic variability are likely to be most common for classical "fitness" (cf. life-history) rather than for "nonfitness" (cf. morphological) traits.
authors.affiliation: Department of Chemistry and Bioscience, Section of Biology and Environmental Science, Aalborg University, Denmark. ary@unimelb.edu.au.|School of BioSciences, Bio21 Institute, The University of Melbourne, Victoria, Australia. ary@unimelb.edu.au.
authors.forename: Ary A
authors.initials: AA
authors.lastname: Hoffmann
authors.affiliation: Department of Biosciences, Ecological Genetics Research Unit, University of Helsinki, Finland.
authors.forename: Juha
authors.initials: J
authors.lastname: Merilä
authors.affiliation: Department of Chemistry and Bioscience, Section of Biology and Environmental Science, Aalborg University, Denmark.
authors.forename: Torsten N
authors.initials: TN
authors.lastname: Kristensen
mesh_terms: D000818:Animals; D005075:Biological Evolution; D001947:Breeding; D002417:Cattle / Q000235:genetics*; D056084:Genetic Fitness; D040582:Inheritance Patterns; D000071421:Life History Traits; D010641:Phenotype
keywords: Additive genetic variance; cattle; environmental variance; fitness; genetic constraints