GENOMIC COADAPTATION AND DEVELOPMENTAL STABILITY WITHIN INTROGRESSED POPULATIONS OF ENNEACANTHUS GLORIOSUS AND E. OBESUS (PISCES, CENTRARCHIDAE).

Using fluctuating bilateral asymmetry as a measure of developmental stability, we tested the hypothesis that genomic coadaptation mediates developmental stability in natural populations. Hybrid populations were more asymmetrical than populations of the parental species, and ranks of overall developmental instability were positively correlated with ranks of mean heterozygosity in these populations. The failure to find increased asymmetry in previous studies of natural hybrid populations (Jackson, 1973a, 1973b; Felley, 1980) suggests that such populations may have re-evolved coadapted genomes. Increased asymmetry in hybrid Enneacanthus populations may reflect the youthfulness of these populations.