Data from: Development of G: a test in an amphibious fish

Heritable variation in, and genetic correlations among, traits determine
the response of multivariate phenotypes to natural selection. However, as
traits develop over ontogeny, patterns of genetic (co)variation and
integration captured by the G matrix may also change. Despite this, few
studies have investigated how genetic parameters underpinning multivariate
phenotypes change as animals pass through major life history stages. Here,
using a self-fertilizing hermaphroditic fish species, mangrove rivulus
(Kryptolebias marmoratus), we test the hypothesis that G changes from
hatching through reproductive maturation. We also test Cheverud’s
conjecture by asking whether phenotypic patterns provide an acceptable
surrogate for patterns of genetic (co)variation within and across
ontogenetic stages. For a set of morphological traits linked to locomotor
(jumping) performance, we find that the overall level of genetic
integration (as measured by the mean-squared correlation across all
traits) does not change significantly over ontogeny. However, we also find
evidence that some trait-specific genetic variances and pairwise genetic
correlations do change. Ontogenetic changes in G indicate the presence of
genetic variance for developmental processes themselves, while also
suggesting that any genetic constraints on morphological evolution may be
age-dependent. Phenotypic correlations closely resembled genetic
correlations at each stage in ontogeny. Thus, our results are consistent
with the premise that – at least under common environment conditions -
phenotypic correlations can be a good substitute for genetic correlations
in studies of multivariate developmental evolution.