title: Genetic evidence of hybridization between the critically endangered Cuban crocodile and the American crocodile: implications for population history and in situ/ex situ conservation.
abstract: Inter-specific hybridization may be especially detrimental when one species is extremely rare and the other is abundant owing to the potential for genetic swamping. The Cuban crocodile (Crocodylus rhombifer) is a critically endangered island endemic largely restricted to Zapata Swamp, where it is sympatric with the widespread American crocodile (C. acutus). An on-island, C. rhombifer captive breeding program is underway with the goals of maintaining taxonomic integrity and providing a source of individuals for reintroduction, but its conservation value is limited by lack of genetic information. Here we collected mtDNA haplotypic and nuclear genotypic data from wild and captive C. rhombifer and C. acutus in Cuba to: (1) investigate the degree of inter-specific hybridization in natural (in situ) and captive (ex situ) populations; (2) quantify the extent, distribution and in situ representation of genetic variation ex situ; and (3) reconstruct founder relatedness to inform management. We found high levels of hybridization in the wild (49.1%) and captivity (16.1%), and additional evidence for a cryptic lineage of C. acutus in the Antilles. We detected marginally higher observed heterozygosity and allelic diversity ex situ relative to the wild population, with captive C. rhombifer exhibiting over twice the frequency of private alleles. Although mean relatedness was high in captivity, we identified 37 genetically important individuals that possessed individual mean kinship (MK) values lower than the population MK. Overall, these results will guide long-term conservation management of Cuban crocodiles for maintaining the genetic integrity and viability of this species of high global conservation value.
authors.affiliation: 1] Departamento de Bioquímica, Facultad de Biología, Universidad de La Habana, Ciudad de La Habana, Cuba [2] Department of Biology, University of British Columbia, Okanagan Campus, Kelowna, British Columbia, Canada.
authors.forename: Y
authors.initials: Y
authors.lastname: Milián-García
authors.affiliation: Empresa Nacional para la Protección de la Flora y la Fauna, Ciudad de La Habana, Cuba.
authors.forename: R
authors.initials: R
authors.lastname: Ramos-Targarona
authors.affiliation: Empresa Nacional para la Protección de la Flora y la Fauna, Ciudad de La Habana, Cuba.
authors.forename: E
authors.initials: E
authors.lastname: Pérez-Fleitas
authors.affiliation: Empresa Nacional para la Protección de la Flora y la Fauna, Ciudad de La Habana, Cuba.
authors.forename: G
authors.initials: G
authors.lastname: Sosa-Rodríguez
authors.affiliation: Empresa Nacional para la Protección de la Flora y la Fauna, Ciudad de La Habana, Cuba.
authors.forename: L
authors.initials: L
authors.lastname: Guerra-Manchena
authors.affiliation: Empresa Nacional para la Protección de la Flora y la Fauna, Ciudad de La Habana, Cuba.
authors.forename: M
authors.initials: M
authors.lastname: Alonso-Tabet
authors.affiliation: Departamento de Bioquímica, Facultad de Biología, Universidad de La Habana, Ciudad de La Habana, Cuba.
authors.forename: G
authors.initials: G
authors.lastname: Espinosa-López
authors.affiliation: Department of Biology, University of British Columbia, Okanagan Campus, Kelowna, British Columbia, Canada.
authors.forename: M A
authors.initials: MA
authors.lastname: Russello
mesh_terms: D000483:Alleles; D000489:Alligators and Crocodiles / Q000235:genetics*; D000818:Animals; D002467:Cell Nucleus / Q000235:genetics; D003247:Conservation of Natural Resources; D003462:Cuba; D004272:DNA, Mitochondrial / Q000235:genetics; D056727:Endangered Species; D005260:Female; D005838:Genotype; D006239:Haplotypes; D006579:Heterozygote; D006824:Hybridization, Genetic; D008297:Male; D018895:Microsatellite Repeats; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D014481:United States
chemical_list: D004272:DNA, Mitochondrial