Cyclura ricordii

Number of Pages: 3Integrative BiologyGeological Science

Cyclura cornuta

Number of Pages: 6Integrative BiologyGeological Science

\u3cem\u3eAnolis\u3c/em\u3e Sex Chromosomes Are Derived from A Single Ancestral Pair

To explain the frequency and distribution of heteromorphic sex chromosomes in the lizard genus Anolis, we compared the relative roles of sex chromosome conservation versus turnover of sex‐determining mechanisms. We used model‐based comparative methods to reconstruct karyotype evolution and the presence of heteromorphic sex chromosomes onto a newly generated Anolis phylogeny. We found that heteromorphic sex chromosomes evolved multiple times in the genus. Fluorescent in situ hybridization (FISH) of repetitive DNA showed variable rates of Y chromosome degeneration among Anolis species and identified previously undetected, homomorphic sex chromosomes in two species. We confirmed homology of sex chromosomes in the genus by performing FISH of an X‐linked bacterial artificial chromosome (BAC) and quantitative PCR of X‐linked genes in multiple Anolis species sampled across the phylogeny. Taken together, these results are consistent with long‐term conservation of sex chromosomes in the group. Our results pave the way to address additional questions related to Anolis sex chromosome evolution and describe a conceptual framework that can be used to evaluate the origins and evolution of heteromorphic sex chromosomes in other clades

Adaptive signal coloration maintained in the face of gene flow in a Hispaniolan Anolis Lizard

Background Studies of geographic variation can provide insight into the evolutionary processes involved in the early stages of biological diversification. In particular, multiple, replicated cases of geographic trait divergence present a powerful approach to study how patterns of introgression and adaptive divergence can vary with geographic space and time. In this study, we conduct replicated, fine-scaled molecular genetic analyses of striking geographic dewlap color variation of a Hispaniolan Anolis lizard, Anolis distichus, to investigate whether adaptive trait divergence is consistently associated with speciation, whereby genetic divergence is observed with neutral markers, or whether locally adapted traits are maintained in the face of continued gene flow. Results We find instances where shifts in adaptive dewlap coloration across short geographic distances are associated with reproductive isolation as well as maintained in the face of gene flow, suggesting the importance of both processes in maintaining geographic dewlap variation. Conclusion Our study suggests that adaptive dewlap color differences are maintained under strong divergent natural selection, but this divergence does not necessarily lead to anole speciation

Anolis sex chromosomes are derived from a single ancestral pair

This is the peer reviewed version of the following article: Gamble, T., Geneva, A. J., Glor, R. E., & Zarkower, D. (2014). Anolis sex chromosomes are derived from a single ancestral pair. Evolution; International Journal of Organic Evolution, 68(4), 1027–1041. http://doi.org/10.1111/evo.12328, which has been published in final form at http://doi.org/10.1111/evo.12328. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.To explain the frequency and distribution of heteromorphic sex chromosomes in the lizard genus Anolis we compared the relative roles of sex chromosome conservation vs. turnover of sex determining mechanisms. We used model based comparative methods to reconstruct karyotype evolution and the presence of heteromorphic sex chromosomes onto a newly generated Anolis phylogeny. We found that heteromorphic sex chromosomes evolved multiple times in the genus. Fluorescent in situ hybridization (FISH) of repetitive DNA showed variable rates of Y chromosome degeneration among Anolis species and identified previously undetected, homomorphic sex chromosomes in two species. We confirmed homology of sex chromosomes in the genus by performing FISH of an X-linked BAC and qPCR of X-linked genes in multiple Anolis species sampled across the phylogeny. Taken together, these results are consistent with long-term conservation of sex chromosomes in the group. Our results pave the way to address additional questions related to Anolis sex chromosome evolution and describe a conceptual framework that can be used to evaluate the origins and evolution of heteromorphic sex chromosomes in other clades

Transcriptomic Analysis of Skin Color in Anole Lizards

Color and color pattern are critical for animal camouflage, reproduction, and defense. Few studies, however, have attempted to identify candidate genes for color and color pattern in squamate reptiles, a colorful group with over 10,000 species. We used comparative transcriptomic analyses between white, orange, and yellow skin in a color-polymorphic species of anole lizard to 1) identify candidate color and color-pattern genes in squamates and 2) assess if squamates share an underlying genetic basis for color and color pattern variation with other vertebrates. Squamates have three types of chromatophores that determine color pattern: guanine-filled iridophores, carotenoid- or pteridine-filled xanthophores/erythrophores, and melanin-filled melanophores. We identified 13 best candidate squamate color and color-pattern genes shared with other vertebrates: six genes linked to pigment synthesis pathways, and seven genes linked to chromatophore development and maintenance. In comparisons of expression profiles between pigment-rich and white skin, pigment-rich skin upregulated the pteridine pathway as well as xanthophore/erythrophore development and maintenance genes; in comparisons between orange and yellow skin, orange skin upregulated the pteridine and carotenoid pathways as well as melanophore maintenance genes. Our results corroborate the predictions that squamates can produce similar colors using distinct color-reflecting molecules, and that both color and color-pattern genes are likely conserved across vertebrates. Furthermore, this study provides a concise list of candidate genes for future functional verification, representing a first step in determining the genetic basis of color and color pattern in anoles

Adaptation, Speciation, and Convergence: A Hierarchical Analysis of Adaptive Radiation in Caribbean Anolis Lizards

This is the publisher's version, also available electronically from http://www.bioone.org/doi/abs/10.3417/0026-6493%282006%2993%5B24%3AASACAH%5D2.0.CO%3B2.Caribbean Anolis lizards are a classic case of adaptive radiation, repeated four times across islands of the Greater Antilles. On each island, very similar patterns of evolutionary divergence have occurred, resulting in the evolution of the same set of ecological specialists—termed ecomorphs—on each island. However, this is only part of the story of the Caribbean anole radiations. Indeed, much of the species diversity of Caribbean Anolis occurs within clades of ecomorphs, which contain as many as 14 ecologically-similar species on a single island. We ask to what extent the classic model of ecological interactions as the driving force in adaptive radiation can account for this aspect of anole evolutionary diversity. Our answer is that it can in part, but not entirely. More generally, the most complete understanding of evolutionary diversification and radiation is achieved by studying multiple hierarchical evolutionary levels from clades to populations

Amphibians and reptiles of the Dominican Republic: species of special concern

The Dominican Republic faces multiple threats to biodiversity. A list of native species of amphibians and reptiles (excluding sea turtles) is presented. Some may have become extinct recently, substantial populations of others have been extirpated, some have greatly reduced numbers, and others appear to be rare or have restricted ranges. Most of the 13 taxa listed are relatively large, vulnerable to human exploitation or introduced predators, and/or have limited distributions and specific habitat requirements. To be listed, evidence must exist that: (1) populations are dwindling, (2) the range is shrinking, or (3) a species must be vulnerable to exploitation and historically rare. Two iguanas (Cyclura cornuta, C. ricordii), two turtles (Trachemys decorata, T. stejnegeri vicina), and one crocodilian (Crocodylus acutus) have been exploited extensively and have long been recognized as threatened or endangered. The ranges of Cyclura ricordii and T. decorata are very localized and the previously widespread ranges of the others have shrunk or become fragmented. A toad (Bufo fluviaticus), a large galliwasp (Celestus anelpistus), and a snake (Alsophis melanichnus) have not been collected recently. Only a few specimens of another galliwasp (C. carraui) and a dwarf gecko (Sphaerodactylus cochranae) have been taken recently. In addition, extensive portions of the habitats of these species have been severely altered. Three other snakes (Alsophis anomalus, Ialtris agyrtes, I. dorsalis) are rare and may never have been common. Their size and habits render them vulnerable to predation by the introduced mongoose and to decimation by humans who fear and dislike them