Data from: Heritable differences in fitness-related traits among populations of the mustard hill coral, Porites astreoides

A population’s potential for rapid evolutionary adaptation can be
estimated from the amount of genetic variation in fitness-related traits.
Inshore populations of the mustard hill coral (Porites astreoides) have
been shown to be more tolerant to thermal stress than offshore
populations, but it is unclear whether this difference is due to long-term
physiological acclimatization or genetic adaptation. Here, we evaluated
variation in growth rate and survival among 38 families of juvenile
recruits of P. astreoides spawned by colonies originating from inshore and
offshore locations. Recruits were reared in a common garden for 5 weeks
and then subjected to two thermal treatments (28  and 31 °C) for 2.5
weeks. The most significant effects were detected during the first 5
weeks, before thermal stress was applied: 27–30% of variance in growth and
94% of variance in recruit survival was attributable to parental effects.
Genotyping of eight microsatellite loci indicated that the high early
mortality of some of the recruit families was not due to higher
inbreeding. Post treatment, parental effects diminished such that only
10–15% of variance in growth rate was explained, which most likely
reflects the dissipation of maternal effects. However, offshore-origin
recruits still grew significantly less under elevated temperature compared
with inshore-origin recruits. These differences observed in naive juvenile
corals suggest that population-level variation in fitness in response to
different thermal environments has a genetic basis and could represent raw
material for natural selection in times of climate change.