O2 – Genetic evidence of hybridization between the endangered native species Iguana Delicatissima and the invasive I. iguana (reptilia, Iguanidae) SESSION 4
SESSION 4
The increase of hybridization worldwide in different groups is thought to become more important with the loss of isolating barriers and the introduction of invasive species. This phenomenon could result in the extinction of endemic species. The aim of this study is to investigate the hybridization dynamics between the endemic and threatened Lesser Antilles iguana (Iguana delicatissima) and the invasive common green iguana (Iguana iguana) in Lesser Antilles and to assess the impact of interspecific hybridization in the decline of I. delicatissima. 59 I. delicatissima (5 localities), 47 I. iguana (12 localities) and 27 hybrids (5 localities) identified on morphological characters have been genotyped at 15 microsatellites markers. Moreover, we also sequenced hybrids at the ND4 mitochondrial loci to further investigate mitochondrial introgression. Species genetic clustering and hybrid genetic assignment were performed using a comparative approach implementing a statistically based discriminant analysis of principal component (DAPC) and several population genetic models based genetic clustering approaches (Structure, NewHybrids and HIest) to get a full characterization of the hybridization pattern and introgression dynamics across islands. The iguanas identified as hybrids in the wild on a morphological analysis were all genetically F1, F2 or backcrosses. There is also a high proportion of individuals resulting from a more long term admixture. The absence of reproductive barriers between species leads to hybridization when species are in contact, yet morphological and behavioral species differences may explained why male I. iguanamay dominate I. delicatissima resulting in short term species displacement and extinction by hybridization and recurrent introgression from I. iguana toward I. delicatissima. As a consequence, I. delicatissima is eliminated through introgression as observed in recent population history in several islands.
