Genetic factors associated with transparency of juvenile red sea bream, Pagrus major

Transparent individuals have been identified in juveniles of a hatchery population of red sea bream. This study characterized the numbers of melanophores, xantphores, and erythrophores, in normal and transparent individuals. The transparent individuals were partly transparent at the 40 day-post-hatch stage and the numbers of all chromatophores were significantly lower. In 100 day-post-hatch juveniles, the transparent individuals exhibited slight differences to normal individuals. However, the numbers of xantphores and erythrophores remained significantly lower. The parentage of normal and transparent individuals was identified by five microsatellite loci. Analysis indicated that normal individuals were generated from 6 female and 8 male parents, and 15 parental pairs were identified. However, all transparent individuals were generated from 1 female with 5 male parents. Our results suggest that the transparent individuals identified in larvae of the hatchery population of red sea bream had arisen via genetic effects.