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

21
Functional genetic diversity and pathogen resistance in black-tailed prairie dogs Liz Harp Colorado State University Graduate Degree Program in Ecology AAVP Meeting • July 2008 Genes, germs, and prairie dogs

Upload: deon

Post on 18-Mar-2016

72 views

Category:

Documents


4 download

DESCRIPTION

Functional genetic diversity and pathogen resistance in black-tailed prairie dogs. Genes, germs, and prairie dogs. Liz Harp Colorado State University Graduate Degree Program in Ecology AAVP Meeting • July 2008. Objective. - PowerPoint PPT Presentation

TRANSCRIPT

Page 1: Functional genetic diversity and pathogen resistance in black-tailed prairie dogs

Functional genetic diversityand pathogen resistance

in black-tailed prairie dogs

Liz HarpColorado State University

Graduate Degree Program in Ecology

AAVP Meeting • July 2008

Genes, germs, and prairie dogs

Page 2: Functional genetic diversity and pathogen resistance in black-tailed prairie dogs

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

Page 3: Functional genetic diversity and pathogen resistance in black-tailed prairie dogs

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

Page 4: Functional genetic diversity and pathogen resistance in black-tailed prairie dogs

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 ComplexAn important part of the adaptive immune systemMore on this later…

Page 5: Functional genetic diversity and pathogen resistance in black-tailed prairie dogs

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

Page 6: Functional genetic diversity and pathogen resistance in black-tailed prairie dogs

Black-tailed prairie dog parasites(a subsample)

Ectoparasites– Oropsylla hirsuta– Oropsylla tuberculata– Pulex simulans– Thrassis fotus– Ornithodoros turicata

Gastrointestinal parasites– Eimeria (4 species expected)– Giardia– Cryptosporidium

Microparasites (antibodies)– Yersinia pestis (gram negative bacterium)

– West Nile Virus (single stranded RNA virus)

Page 7: Functional genetic diversity and pathogen resistance in black-tailed prairie dogs

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

Page 8: Functional genetic diversity and pathogen resistance in black-tailed prairie dogs

Hypothesis• Specific alleles in immune system genes will

provide some level of resistance to particular parasites or groups of parasites

Page 9: Functional genetic diversity and pathogen resistance in black-tailed prairie dogs

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)

Page 10: Functional genetic diversity and pathogen resistance in black-tailed prairie dogs

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

Page 11: Functional genetic diversity and pathogen resistance in black-tailed prairie dogs

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

Page 12: Functional genetic diversity and pathogen resistance in black-tailed prairie dogs

Field methods• Short Grass Steppe Long Term

Ecological Research Area (Pawnee National Grassland)

• Three prairie dog colonies~18km

~12km

~9km

Avg dispersal distance: 1.8 – 2.7km Max dispersal distance: 5.7 – 9.6km

Page 13: Functional genetic diversity and pathogen resistance in black-tailed prairie dogs

Field methods• Pawnee National Grassland• Live-trap black-tailed prairie dogs

June – November 2007 ; April – November 2008

Page 14: Functional genetic diversity and pathogen resistance in black-tailed prairie dogs

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

Page 15: Functional genetic diversity and pathogen resistance in black-tailed prairie dogs

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

Page 16: Functional genetic diversity and pathogen resistance in black-tailed prairie dogs

Field methods• Pawnee National Grassland• Live-trap black-tailed

prairie dogs• Collect fleas, feces,

blood, and tissue• Record age, sex, and weight• Mark each animal with numbered ear tags

Page 17: Functional genetic diversity and pathogen resistance in black-tailed prairie dogs

Capture Recordsthrough July 14, 2007

TOTAL 2007June - Nov

2008 (in progress)April - Nov

2007 & 2008

Unique individuals 192 108 68 16

Caught 1x 120 63% 72 48 0

Caught 2x 41 21% 22 13 6 (1/1)

Caught 3x 20 10% 10 5 5 (2/1 ; 1/2)

Caught 4x 3 2% 2 0 1 (2/2)

Caught 5x 6 3% 2 2 2 (4/1)

Caught 6x 1 0.5% 0 0 1 (4/2)

Caught 7x 1 0.5% 0 0 1 (1/6)

Original capture < 2007 61 32% 43 10 8

Page 18: Functional genetic diversity and pathogen resistance in black-tailed prairie dogs

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

Page 19: Functional genetic diversity and pathogen resistance in black-tailed prairie dogs

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

Page 20: Functional genetic diversity and pathogen resistance in black-tailed prairie dogs

Invaluable help, advice, and funding…Mike AntolinLora BallweberDan TrippShelley Bayard de VoloChris SymmesSarah O’NeilFunding:National Science FoundationSigma XiAmerican Society of Mammalogists

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

All photos were either taken by me, my students, or other people I know, or are from WikiMedia Commons.

Page 21: Functional genetic diversity and pathogen resistance in black-tailed prairie dogs

Questions?Comments?