Estimating heritability in honeybees: comparison of three major methods
based on empirical and simulated datasets.
Abstract
The level of the genetic contribution to phenotypic variation (namely
the heritability) determines the response to selection. In honeybee, the
haplodiploid sex determination does not allow the straightforward use of
classical quantitative genetics methods to estimate heritability and
genetic correlation. Nevertheless, specific methods have been developed
for about 40 years. In particular, sib-analyses are frequently used with
three main methods: an historical model using the average colony
relatedness, a half-sibs/full-sibs model and the more recent animal
model. We compared those three methods using experimental and simulated
datasets to see which performs the best. Our experimental dataset is
composed of 10 colonies with 853 workers in total. All individuals were
genotyped to reconstitute the pedigree, and phenotypic traits were
measured: the proboscis- and wing-associated lengths. We also simulated
phenotypic datasets with varying levels of heritability, common
environmental effect and genetic correlation between traits. The
simulation approach showed that the average colony relatedness was
highly biased in presence of common environmental effect whereas the
half-sibs/full-sibs and the animal model gave reliable estimates of
heritability. The animal model provided the greatest precision in
genetic correlations. Using this latter method, we found that
wing-related traits had high heritabilities, allowing the use of those
morphometric characters to discriminate between populations. On the
contrary, the palpus length (associated to proboscis) was more sensitive
to environmental factors. Finally, significant genetic correlations
among measured traits indicate that they do not evolve independently.