Functional genetic diversity and pathogen resistance in black-tailed prairie dogs

1. Functional genetic diversityand pathogen resistancein black-tailed prairie dogs Genes, germs, and prairie dogs Liz Harp Colorado State University Graduate Degree Program in Ecology AAVP Meeting • July 2008

2. Objective • Compare parasite species richness and numbers of parasites to genetic diversity in 4 immune system genes and 10 microsatellite loci in black-tailed prairie dogs • Use this information to: • Identify relationships between immunogenetic diversity and parasite numbers and diversity • Compare neutral vs. functional genetic markers for use in conservation management

3. Motivation and brief background… parasites • Parasites are important in wildlife conservation • Rarely cause extinction directly, but… • May help maintain genetic variation • Parasites are rarely considered inwildlife conservation plans unless they are obviously impacting a population

4. Motivation and brief background… genetics • Conservation genetic markers typically neutral • Microsatellites, SNPs (good for population genetics) • Functional markers might be better for monitoring populations & breeding programs • Immune system genes, … • Lots of recent research with MHC* diversity • But what about other functional genetic markers? *Major Histocompatibility Complex An important part of the adaptive immune system More on this later…

5. Motivation and brief background… prairie dogs • Social burrowing rodents in the squirrel family • Abundant in eastern Colorado • Plague outbreaks are common • They have a lot of parasites, sort of • Five prairie dog species • One threatened, one endangered,others frequently petitioned for listing

6. Black-tailed prairie dog parasites(a subsample) Ectoparasites • Oropsyllahirsuta • Oropsyllatuberculata • Pulexsimulans • Thrassisfotus • Ornithodorosturicata • Gastrointestinal parasites • Eimeria (4 species expected) • Giardia • Cryptosporidium • Microparasites (antibodies) • Yersinia pestis (gram negative bacterium) • West Nile Virus (single stranded RNA virus)

7. Eimeria recorded from black-tailed prairie dogs* • E. beecheyi(Casper, WY) • E. callospermophili(Casper, WY) • E. cynomysis(northern Colorado) • E. lateralis(N. Colorado; SW North Dakota; Casper, WY) • E. ludoviciani(N. Colorado; SW North Dakota) • E. morainensis(Casper, WY) • E. pseudospermophili(Casper, WY) • E. spermophili(Casper, WY) • E. vilasi(Casper, WY) * Names corrected from original sources according to Wilbur et al. 1998

8. Hypothesis • Specific alleles in immune system genes will provide some level of resistance to particular parasites or groups of parasites

9. Immune genes of interest • Toll-like receptors 2 & 4 • Pattern recognition molecules • Found on dendritic cells, macrophages, and neutrophils • Viruses, bacteria, protozoa, fungi, and helminths (TLR 2)

10. Immune genes of interest • Toll-like receptors 2 & 4 • Chemokine receptor 5 • Found on dendritic cells, macrophages, and CD4 T cells • Involved in immune cell chemotaxis • Used by HIV to gain entry to target cells • Hypothesized link to plague immunity

11. Immune genes of interest • Toll-like receptors 2 & 4 • Chemokine receptor 5 • Class II Major Histocompatibility Complex DRB-1 • Highly polymorphic • Found on dendritic cells, macrophages, and B cells • Presents extracellular antigens to helper T cells • Many studies using a variety of wild vertebrates • Parasites, demographic history, mate-choice,selection mechanisms

12. Field methods • Short Grass Steppe Long Term Ecological Research Area (Pawnee National Grassland) • Three prairie dog colonies ~12km ~18km ~9km Avg dispersal distance: 1.8 – 2.7km Max dispersal distance: 5.7 – 9.6km

13. Field methods • Pawnee National Grassland • Live-trap black-tailed prairie dogs June – November 2007 ; April – November 2008

14. Field methods • Pawnee National Grassland • Live-trap black-tailed prairie dogs • Collect fleas, feces, blood, and tissue

15. Field methods • Pawnee National Grassland • Live-trap black-tailed prairie dogs • Collect fleas, feces, blood, and tissue • Record age, sex, and weight

16. Field methods • Pawnee National Grassland • Live-trap black-tailedprairie dogs • Collect fleas, feces,blood, and tissue • Record age, sex, and weight • Mark each animal with numbered ear tags

17. Capture Recordsthrough July 14, 2007

18. Laboratory methods • Quantify and identify: • Eimeria spp. • Cryptosporidium and Giardia • Fleas and ticks • Test for antibodies to: • West Nile Virus • Yersinia pestis (plague) • SSCP analysis to determine immune gene alleles • Microsatellite analysis • Neutral control, relatedness

19. Anticipated results(i.e., why this research is important) • Develop adaptive genetic markers that will be useful in conservation for all 5 species of prairie dog • Contribute to current knowledge of the genetic basis for susceptibility and resistance to disease • Provide a current survey of black-tailed prairie dog parasites on the Pawnee National Grassland

20. Invaluable help, advice, and funding… Students and Volunteers (field): Allison Fockler, Alyssa Christ, Heather Craven, Holly Meltesen, Janelle Trujillo, Jennie Skinner, Kelsey Toth, Marie Stiles, Nicole McDaniel, Paul Stearman, Rebecca Blaskovich, Sarah Legare, Sarah O’Neil, Sean Streich, Sorrell Redford, Tori Wheeler, Tyler Tretten, and all of the ecology students and teachers who came out for a few days to see what we do out there Students and Volunteers (lab): Alex Ard, Helen Lepper, Jen Austin, Sarah Legare, Sarah O’Neil Mike Antolin Lora Ballweber Dan Tripp Shelley Bayard de Volo Chris Symmes Sarah O’Neil Funding: National Science Foundation Sigma Xi American Society of Mammalogists All photos were either taken by me, my students, or other people I know, or are from WikiMedia Commons.

21. Questions? Comments?