Genetics

POPULATION GENETICS AND PHYLOGEOGRAPHY

CALIFORNIA CHANNEL ISLANDS PHYLOGEOGRAPHY

The California Channel Islands, located just off the coast of southern California, is home to several endemic species. In collaboration with W. Chris Funk and Patricia Salerno (Colorado State University) and Greg Pauly (The Natural History Museum of Los Angeles County) we are conducting a comprehensive phylogeographic study Channel Island populations of amphibians and reptiles and the diversification of island populations (relative to the mainland). We are using both Sanger sequencing and Next Generation Sequencing approaches to address evolutionary history of this region.

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View from a ridge on Santa Cruz Island (California Channel Island)

 

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Side-blotched lizard, Catalina Island

 

LANDSCAPE GENETICS OF THE WESTERN FENCE LIZARD

We are conducting a landscape genetics study of Sceloporus occidentalis becki on Santa Cruz Island (Channel Islands National Park). Landscape genetics seeks to understand the role of environmental variables (habitat and climate) on the genetic connectivity of populations. Santa Cruz Island is ideal for a landscape study, due to its diverse habitats and dramatic topographic relief. Further, there are substantial climatic differences across the island, resulting in hot, dry habitats on southern and western slopes, and cool, wet habitats on some eastern and northern slopes. This research will help characterize variation in habitat and climate on the island and further identify how this impacts genetic variation in a unique Channel Island species.

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Sceloporus occidentalis becki on Santa Cruz Island

 

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Ventral color pattern analyses of S. occidentalis becki on Santa Cruz Island.

GENETIC AND PHENOTYPIC DIVERSIFICATION: TALE OF TWO CLINES

 Agalychnis callidryas, the Red-Eyed Treefrog, has the largest geographic distribution of Central American phyllomedusine frogs – it is unique in that it is the only polytypic species in this group. Previously, we combined analyses of geographic variation in phenotypic diversity among Costa Rican and Panamanian population with phylogenetic and population genetic studies to reveal the combined roles of geographic isolation, gene flow and selection for color pattern diversification. We have narrowed our focus on patterns of genomic change along two independent clines, with attention to a narrow contact zone for each cline using a RADseq approach (work of MS student M. Akoypan).

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Map of Costa Rica and Panama showing the geographic distribution of color morphs of Red-eyed treefrogs

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Phylogenetic relationship of Red-eyed treefrog populations from Costa Rica and Panama.

Gallery of color morphs of Red-eyed treefrogs.

Above: Flank color pattern, Below: leg color pattern)

Flank color pattern variation among populations of Red-eyed treefrogs.

Flank color pattern variation among populations of Red-eyed treefrogs.

Color pattern variation in Red-eyed treefrogs: leg color pattern for populations across Costa Rica and Panama

Color pattern variation in Red-eyed treefrogs: leg color pattern for populations across Costa Rica and Panama

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