Invasive invertebrates associated with highly duplicated gene content.

Invasion of alien species has led to serious problems, including the destruction of native ecosystems. In general, invasive species adapt to new environments rapidly, suggesting that they have high genetic diversity that can directly influence environmental adaptability. However, it is not known how genomic architecture causes genetic diversity that leads to invasiveness. Recent studies have showed that the proportion of duplicated genes (PD ) in whole animal genomes correlate with environmental variability within a habitat. Here, we show that PD and propagule size significantly explain the differences in species categories (invasive species, noninvasive species, and parasites). PD correlated negatively with the propagule size. The residual values of regression of PD on propagule size revealed that the invasive species had higher PD values and larger propagule size than those of the noninvasive species, whereas the parasites had lower PD values and smaller propagule size than those of others. There were no correlations between the invasive species and other genomic factors including the genome size, number of genes, and certain gene families. Our results suggest that the PD values of a genome might be a potential genomic source causing genetic variations for adaptation to diverse environments. The results also showed that the invasiveness status of a species would be predicted by the residual values of regression of PD on propagule size. Our innovative approach provides a measure to estimate the environmental adaptability of organisms based on genomic data.