October 11 2018

5:00 pm 1100 TLSB

EcoEvoPub Series

Graduate Student Presentations


Department of Ecology and Evolutionary Biology, UCLA

“RNA-seq and ecophysiology measurements reveal both species-wide and population-specific responses to water stress in valley oak (Quercus lobato) seedlings”

Drought is a major stress for plants and creates strong selection pressure on traits that allow plants to grow and survive in local environments. Many drought responses are conserved, species-wide responses while other responses differ among populations, which are distributed across heterogeneous environments and experience dissimilar local selection pressures. This study tests whether populations of valley oak (Quercus lobata), a widely-distributed California endemic oak, differ in their response to water stress. Seedlings were sampled from contrasting climates across California and exposed to a well-watered or soil drying treatment in order to determine how gene expression and ecophysiology traits would respond in each population. Populations did not differ in the response of turgor loss point and leaf water potential, suggesting a generalized species-wide response. However, several groups of genes, or gene “modules,” were identified using weighted gene co-expression analysis (WGCNA) which responded differently to water stress among populations, identifying potential differences in gene network regulation. Seedlings from sites with a high mean annual temperature had a stronger and more complex response, with more modules responding and greater changes in expression. These genes may be involved in acclimation during the early stages of drought stress. This study provides evidence that valley oak populations are locally adapted to respond to water stress. As drought is projected to increase in California due to climate change, this may be useful for predicting the response of different populations and devising management strategies.

Department of Ecology and Evolutionary Biology, UCLA

“Conservation genetics in the age of high-throughput sequencing - new tools and old dilemmas”

California is a biological hotspot due to complex geological and climatological history. Recent anthropogenic impacts on the landscape have had major impacts on the local fauna, especially those associated with wetland habitats. Such is the case of the rare and endangered unarmored threespine stickleback; a species of unionid clam from the Los Angeles, San Gabriel and Santa Ana Rivers; and lastly, a species of freshwater shrimp endemic to the Los Angeles Basin that is now extinct. Advancements in molecular techniques have allowed us to unravel genomic signals of demography and evolution, investigate ancient and extinct species, and even look at environmental samples. This presentation will be an overview of my dissertation where I explore the use of high-throughput sequencing and bioinformatic tools to target relevant conservation issues related to endangered species and habitats in southern California.











































































































































































































































































































































































































































































































































































































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