Marine Invasion Genomics: Revealing Ecological and Evolutionary Consequences of Biological Invasions

Abstract

Population genetics/genomics investigates gene flow, genetic diversity within and between populations, inbreeding, and effective population size, among other parameters. We here review the literature available on this topic in early-splitting lineages of metazoans. To date, it has been demonstrated the existence of great variation in population genetic patterns in marine invertebrates, because genetic structure results from the interplay of both biological and physical factors at different temporal and spatial scales, and the complexity of these processes are not yet well known. This gap in knowledge limits our ability to predict connectivity patterns according to species' biological traits and environmental factors. A general conclusion of our review is that in most sponges and brooding cnidarians, the short-dispersal potential of the larvae, together with oceanographic circulation, is behind the strong genetic structure observed; whereas species with long pelagic larval duration (e.g. some broadcast spawners) or planktonic adults (jellyfish and ctenophores) display large variation in genetic patterns, from panmixia to local structuring, because a long pelagic life stage does not always ensure connectivity at large spatial scales. Additionally, different contribution of 2 asexual propagation to local recruitment across phyla may also influence populations' structure. The future use of genome-wide scans across the whole genome of the species, together with oceanographic modeling and methodologies to measure larval dispersal will provide us with meaningful data to understand the role of biotic and abiotic factors driving genetic patterns in marine metazoans, and to make predictions about genetic trends with implications for conservation and management.