Browsing by Author "D'Elia, Guillermo"

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    Local adaptation of Dromiciops marsupials (Microbiotheriidae) from southern South America: Implications for species management facing climate change
    (2024) Quintero-Galvis, Julian F.; Saenz-Agudelo, Pablo; D'Elia, Guillermo; Nespolo, Roberto F.
    The two species of the microbiotheriid marsupial genus Dromiciops (Dromiciops bozinovici: "Panchos's monito del monte" and Dromiciops gliroides: "monito del monte") exhibit a marked latitudinal genetic differentiation. Nevertheless, it is unclear whether this differentiation results from neutral processes or can be explained, to some extent, by local adaptation to different environmental conditions. Here, we used an SNP panel gathered by Rad-seq and searched for footprints of local adaptation (putative loci under selection) by exploring genetic associations with environmental variables in the two species of Dromiciops in Chilean and Argentinean populations. We applied three methods for detecting outlier SNPs and two genotype-environment associations approaches to quantify associations between allelic frequencies and environmental variables. Both species display strong genetic structure. D. bozinovici exhibited three distinct genetic groups, marking the first report of such structuring in this species using SNPs. In contrast, D. gliroides displayed four genetic clusters, consistent with previous studies. Both species exhibited an association of their genetic structure with environmental variables. D. bozinovici exhibited significant associations of allelic frequencies with elevation, precipitation during the warmest periods, and seasonality in the thermal regime. For D. gliroides, genetic variation appeared to be associated with more variables than D. bozinovici, including precipitation and temperature-related variables, isothermality, and elevation. All the outlier SNPs were mapped to the D. gliroides reference genome to explore if they fell within functionally known genes. These results represent a necessary first step toward identifying the genome regions that harbor genes associated with climate adaptations in Dromiciops. Notably, we identified genes involved in various functions, including carbohydrate synthesis (ALG8), muscle and neuronal regulation (MEF2D), and stress responses (PTGES3). Ultimately, this study contributes valuable insights that can inform targeted conservation strategies aimed at preserving the genetic diversity of Dromiciops in the face of environmental challenges.
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    Species groups and the evolutionary diversification of tuco-tucos, genus Ctenomys (Rodentia: Ctenomyidae)
    (2011) Parada, Andres; D'Elia, Guillermo; Bidau, Claudio J.; Lessa, Enrique P.
    We present the most comprehensive study to date of species groups in Ctenomys (tuco-tucos), a species-rich genus of Neotropical rodents. To explore phylogenetic relationships among 38 species and 12 undescribed forms we sequenced the complete mitochondrial cytochrome-b genes of 34 specimens and incorporated 50 previously published sequences. Parsimony, likelihood, and Bayesian phylogenetic analyses were performed using additional hystricognath rodents as outgroup taxa. The basal dichotomy of Ctenomys splits C. sociabilis from the remaining tuco-tucos, within which 8 main species groups were identified: boliviensis, frater, mendocinus, opimus, magellanicus, talarum, torquatus, and tucumanus. Whereas most of these groups refer to previous clades proposed on the basis of chromosomes or morphology, the torquatus and magellanicus species groups are novel taxonomic hypotheses. However, relationships among species groups are poorly resolved. Furthmore, the positions of C. leucodon, C. maulinus, and C. tuconax are conflicting or unresolved, and they might represent additional independent lineages. On the basis of molecular dating, we estimate that most species groups originated approximately 3 million years ago.
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    The population of Ctenomys from the Nacunan Biosphere Reserve (Mendoza, Argentina) belongs to Ctenomys mendocinus Philippi, 1869 (Rodentia: Ctenomyidae): molecular and karyotypic evidence
    (2012) Parada, Andres; Ojeda, Agustina; Tabeni, Solana; D'Elia, Guillermo
    Subterranean tuco-tucos of the genus Ctenomys are caviomorph rodents comprising a complex of over 50 nominal species found in the southern half of South America. The validity of several nominal forms awaits a proper assessment. The population of Ctenomys from Nacunan Biosphere Reserve (Mendoza, Argentina) has been classically considered to represent a distinct species and has been commonly referred as Ctenomys "eremofilus". Based on molecular and cytogenetic analysis we assessed the taxonomic status of the Ctenomys population of Nacunan. Specimens analyzed showed two very similar chromosome complements (2n=48 and 2n=50), the latter being widely distributed in populations of C. mendocinus. Similarly, haplotypes recovered from Nacunan specimens are very similar and sister to those recovered from specimens of C. mendocinus. Considering this evidence we conclude that the individuals of Ctenomys from Nacunan population should be assignable to C. mendocinus.