One of the most relevant topics in the biology of invasion concerns the genetic changes that occur subsequent to a species invasion, an issue of particular focus among conservation biologists. Colonizing a novel environment presents a genetic challenge to invading species because such species surely have not experienced the selective pressures presented by the environment. Here we ask, by what mechanisms and processes do alien species genetically naı¨ve to their new environment, become successful invaders? We attempt to resolve this paradox by considering the interplay between an invader's ability to modify its new environment, and genetic modifications imposed by the new environment. We postulate that epigenetic adaptations, and adaptive mutations are likely play a role in enhancing invasion success.

Specimens taken from natural populations of the scallop, Euvola ziczac (L.), were mass spawned in order to produce an initial stock of parents for a selection experiment. The purpose of the present study was to improve scallop shell growth and to calculate the degree of heritability of this characteristic. At one year of age, the top 10% of the stock (i.e. the larger scallops) were segregated to create the selected line. An equal number of mean-sized scallops was used to create the control line. In the second generation, after 294 days in culture, the heritability values of the scallops were calculated. Heritability estimates¯uctuated between 0.47 and 0.54 depending on the character investigated, i.e. shell length or shell height. The selected line was 5.5% longer and 4.5% higher than the control line, and 7.3% longer and 9.4% higher than the parental line.