title: Genetic Evidence of Hybridization between the Endangered Native Species Iguana delicatissima and the Invasive Iguana iguana (Reptilia, Iguanidae) in the Lesser Antilles: Management Implications.
abstract: The worldwide increase of hybridization in different groups is thought to have 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. This study aims at investigating the hybridization dynamics between the endemic and threatened Lesser Antillean iguana (Iguana delicatissima) and the invasive common green iguana (Iguana iguana) in the Lesser Antilles, as well as assessing the impact of interspecific hybridization on the decline of I. delicatissima. 59 I. delicatissima (5 localities), 47 I. iguana (12 localities) and 27 hybrids (5 localities), who were all identified based on morphological characters, have been genotyped at 15 microsatellites markers. We also sequenced hybrids using ND4 mitochondrial loci to further investigate mitochondrial introgression. The genetic clustering of species and hybrid genetic assignment were performed using a comparative approach, through the implementation of a Discriminant Analysis of Principal Component (DAPC) based on statistics, as well as genetic clustering approaches based on the genetic models of several populations (Structure, NewHybrids and HIest), in order to get full characterization of hybridization patterns and introgression dynamics across the islands. The iguanas identified as hybrids in the wild, thanks to morphological analysis, were all genetically F1, F2, or backcrosses. A high proportion of individuals were also the result of a longer-term admixture. The absence of reproductive barriers between species leads to hybridization when species are in contact. Yet morphological and behavioral differences between species could explain why males I. iguana may dominate I. delicatissima, thus resulting in short-term species displacement and extinction by hybridization and recurrent introgression from I. iguana toward I. delicatissima. As a consequence, I. delicatissima gets eliminated through introgression, as observed in recent population history over several islands. These results have profound implications for species management of the endangered I. delicatissima and practical conservation recommendations are being discussed in the light of these findings.
authors.affiliation: Muséum national d'Histoire naturelle, Laboratoire des Reptiles et Amphibiens, Bâtiment 30, 57, rue Cuvier, CP n° 30, 75231, Paris, cedex 05, France; Laboratoire Genindexe, 7 rue des Sports, 17000, La Rochelle, France.
authors.forename: Barbara
authors.initials: B
authors.lastname: Vuillaume
authors.affiliation: Laboratoire Ecologie et Biologie des Interactions, équipe: Ecologie, Evolution, Symbiose, UMR CNRS 7267, Université de Poitiers, 6 rue Michel Brunet, 86022, Poitiers, Cedex, France.
authors.forename: Victorien
authors.initials: V
authors.lastname: Valette
authors.affiliation: INRA, UMR 1224, Ecologie Comportementale et Biologie des Populations de Poissons, Saint Pée sur Nivelle, France; Univ. Pau & Pays Adour, UMR 1224, Ecologie Comportementale et Biologie des Populations de Poissons, Anglet, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Lepais
authors.affiliation: Laboratoire Ecologie et Biologie des Interactions, équipe: Ecologie, Evolution, Symbiose, UMR CNRS 7267, Université de Poitiers, 6 rue Michel Brunet, 86022, Poitiers, Cedex, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Grandjean
authors.affiliation: Muséum national d'Histoire naturelle, Laboratoire des Reptiles et Amphibiens, Bâtiment 30, 57, rue Cuvier, CP n° 30, 75231, Paris, cedex 05, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Breuil
mesh_terms: D000818:Animals; D016000:Cluster Analysis; D016002:Discriminant Analysis; D056727:Endangered Species; D014644:Genetic Variation; D005838:Genotype; D006239:Haplotypes; D006824:Hybridization, Genetic; D007076:Iguanas / Q000235:genetics*; D058865:Introduced Species; D008297:Male; D008390:Markov Chains; D018895:Microsatellite Repeats / Q000235:genetics; D008928:Mitochondria / Q000235:genetics; D009245:NADH Dehydrogenase / Q000235:genetics; D025341:Principal Component Analysis
chemical_list: D009245:NADH Dehydrogenase