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Browsing by Author "Poulakakis, Nikos"

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    Galapagos giant tortoise trafficking case demonstrates the utility and applications of long-term comprehensive genetic monitoring
    (2023) Quinzin, Maud C.; Bishop, Anusha P.; Miller, Joshua M.; Poulakakis, Nikos; Tapia, W.; Torres-Rojo, F.; Sevilla, C.; Caccone, Adalgisa
    Illegal Wildlife Trade (IWT) is a cause for global concern as pressure stemming from IWT threatens wild species and can even lead to extinction. Galapagos giant tortoises (Chelonoidis sp.) are a group of threatened species protected under CITES, which forbids their import–export for international trade; however, IWT of this group persists. In this study, we describe the use of two extensive genetic repositories of mitochondrial and nuclear microsatellite markers for Galapagos giant tortoises to identify an unsuspected source of trafficked juvenile tortoises. Our genetic analyses, together with morphological and captive-born registry data, provide evidence that the smuggled juveniles were from two breeding centers dedicated toward conservation located on the Galapagos islands of San Cristobal and Isabela. This is the first documentation of smuggled tortoises being taken from breeding centers rather than the wild. The findings from our genetic analysis provided key evidence that enabled legal investigation. This case demonstrates the importance of the comprehensive genetic characterization of Galapagos giant tortoises and the suitability of standard genetic markers for identifying the species and islands of origin of trafficked animals. We also discuss the efficacy, adequacy, and reach of existing measures against IWT. Overall, this case illustrates an important application of long-term and comprehensive genetic repositories of endangered species and the crucial role of collaborations among academic laboratories maintaining those repositories, local practitioners responsible for species protection, and the bodies that implement and enforce antitrafficking regulations.
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    A new lineage of Galapagos giant tortoises identified from museum samples
    (2022) Jensen, Evelyn L.; Quinzin, Maud C.; Miller, Joshua M.; Russello, Michael A.; Garrick, Ryan C.; Edwards, Danielle L.; Glaberman, Scott; Chiari, Ylenia; Poulakakis, Nikos; Tapia, Washington; Gibbs, James P.; Caccone, Adalgisa
    The Galapagos Archipelago is recognized as a natural laboratory for studying evolutionary processes. San Cristóbal was one of the first islands colonized by tortoises, which radiated from there across the archipelago to inhabit 10 islands. Here, we sequenced the mitochondrial control region from six historical giant tortoises from San Cristóbal (five long deceased individuals found in a cave and one found alive during an expedition in 1906) and discovered that the five from the cave are from a clade that is distinct among known Galapagos giant tortoises but closely related to the species from Española and Pinta Islands. The haplotype of the individual collected alive in 1906 is in the same clade as the haplotype in the contemporary population. To search for traces of a second lineage in the contemporary population on San Cristóbal, we closely examined the population by sequencing the mitochondrial control region for 129 individuals and genotyping 70 of these for both 21 microsatellite loci and >12,000 genome-wide single nucleotide polymorphisms [SNPs]. Only a single mitochondrial haplotype was found, with no evidence to suggest substructure based on the nuclear markers. Given the geographic and temporal proximity of the two deeply divergent mitochondrial lineages in the historical samples, they were likely sympatric, raising the possibility that the lineages coexisted. Without the museum samples, this important discovery of an additional lineage of Galapagos giant tortoise would not have been possible, underscoring the value of such collections and providing insights into the early evolution of this iconic radiation.