Heritability of morfological and life history traits in a pelagic tunicate

LOBON, C; ACUÑA, J.L; LOPEZ-ALVAREZ M; CAPITANIO, F; GONZALES, E

Niza, Francia

Congreso; ASLO; 2009

ASLO

Populations may adapt in response to selection pressures imposed by global environmental change. Yet the potential for evolution among marine planktonic organisms remains an understudied topic, and measurements of heritability are still rare. Here we demonstrate the feasibility of conducting assortative mating experiments with the dioecious appendicularian Oikopleura dioica to explore the narrow-sense heritability and genetic correlation among morphological and life-history traits. At our standard laboratory conditions, mature females were larger (1.214 ± 0.19 mm, mean±SD) and lived longer (8.508 ± 2.18 d) than males (1.115 ± 0.15 mm, 7.645 ± 2.07 d). The heritability (±SE) of morphological characters was low (body size, 0.03 ± 0.16) or moderate (gonad, 0.31 ± 0.28; house, 0.38 ± 0.26; tail size, 0.48 ± 0.29). In contrast, life-history traits showed moderate (clutch size, 0.32 ± 0.30) and high heritabilities (lifespan, 1.03 ± 0.47) and may therefore respond rapidly to selection pressure. Significant genetic correlations found indicate that animals evolving shorter lifespans in response to increasing temperatures would have smaller houses and tails, but gonads relatively bigger, resulting in an enhanced rate of natural increase.