1 / 18

Proposed Research Jonathan Warner Atwell Timothy James Grieves Dawn Michelle O’Neal

Physiological and genetic mechanisms underlying population divergence across an altitudinal gradient. Proposed Research Jonathan Warner Atwell Timothy James Grieves Dawn Michelle O’Neal. Introduction.

athena-wilcox
Download Presentation

Proposed Research Jonathan Warner Atwell Timothy James Grieves Dawn Michelle O’Neal

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Physiological and genetic mechanisms underlying population divergence across an altitudinal gradient Proposed Research Jonathan Warner Atwell Timothy James Grieves Dawn Michelle O’Neal

  2. Introduction • Understanding mechanisms that underlie adaptive divergence is a central goal of evolutionary biology and ecology • Investment in reproduction vs. survival is a ubiquitous life-history trade-off, and optimal strategies should vary with environment • Few studies have robustly characterized physiological and genetic substrates of divergent life-history strategies

  3. Local adaptation to seasonal environments • Breeding season length varies with latitude • Life-history traits also vary with breeding season & latitude, including testosterone and immune function • Similar differences are seen across an altitudinal gradient From Bronson 1990

  4. General Questions • How has selection shaped the regulatory physiology of divergent mouse populations across an altitudinal gradient? • Breeding phenology • Seasonal testosterone & immune function • What are the genetic mechanisms underlying physiological variation? • Divergent candidate genes

  5. Rocky Mountain Biological Laboratory

  6. Alpine tundra Subalpine forest prairie grasslands (Storz et al. 2004)

  7. Field Capture methods • Capture in baited sherman traps • Sample February-September • Morphological measures • Assessment of reproductive condition (fondling) • Retro-orbital blood sample • Ear-tag and release

  8. Alpine tundra Breeding season Subalpine forest Prairie grasslands

  9. Measuring seasonal T and Innate Immune Function profiles… -Capture free-living individuals each month before, during, & after breeding in both populations -Collect sub-orbital blood samples -Centrifuge blood, freeze plasma -Conduct EIA assays to measure [ T ] -Bacterial Killing Assays (Petri Dishes) -Heamolytic Complement (EIA Plate)

  10. Y = anti-testosterone antibody Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y = hormone in serum sample = labeled hormone of known amount Y Y Y Y Y Y Y Y Y Y Y Y Color Y Y Y Y Y Y How do you measure hormones?

  11. Hypothesis: seasonal variation in T expression T T Mountain Mice Prairie Mice T T

  12. Immune Function • Innate • Nonspecific antigen defense mechanisms • Bactericidal assay • Measure of susceptibility • Hemolytic complement • Measure of ability to respond • Acquired/adaptive • Developed in response to specific antigens • KLH • Antibody production

  13. Subalpine forest Alpine tundra Prairie grassland

  14. Altitude Alpine Tundra Subalpine Forest Prairie Grasslands 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 CH50 Hemolytic Complement Activity by Altitude

  15. 80 60 40 20 0 Acquired Immune Response (KLH) Alpine Tundra Prairie Grasslands anti-KLH IgG (% plate positive)

  16. Common garden study… -Differences in behavior, hormones, immunity could be genetic or plastic -Collect 20 males and females from each population from early in life (or pregnant females). -Establish in common captive rearing conditions -Collect same measures across season, as in free-living studies -We expect to document genetic change underlying phenotypic divergence. G vs. E ?

  17. Microarray study to identify important loci... -Construct cDNA library -Sacrifice individuals during peak breeding from each free-living population -Compare gene expression profiles -Bayesian statistics to identify genes that differ -Use molecular database to evaluate roles of genes that differ between populations

  18. Conclusions • Utilizing a wide array of methods and techniques, we will be able to assess the mechanisms underlying divergence in breeding phenology, hormonal, and immunological traits. Broader Impacts: -Train a diverse group of undergraduates, high-schoolers, and senior “citizen scientists,” in field and lab methods. -Identify crucial physiological and genetic mechanisms that influence the ability of populations to persist in differing environments (e.g. global climate change, habitat destruction, disease epidemiological patterns) -Dissemination of our results will include public outreach programs (e.g. “A Moment of Science,” Discovery Channel for Kids, National Geographic, Fox News’s “Nutty Professors”).

More Related