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A review Conservation Genetic Analysis of the Texas State Bison Herd

A review Conservation Genetic Analysis of the Texas State Bison Herd. Halbert N . D ., T. Raudsepp , B. P. Chowdhary , J. N. Derr Journal of Mammalogy , 85(5):924-931, 2004. Presented by Caitlin Pyle. The American Bison ( Bos bison ).

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A review Conservation Genetic Analysis of the Texas State Bison Herd

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  1. A reviewConservation Genetic Analysis of the Texas State Bison Herd Halbert N. D., T. Raudsepp, B. P. Chowdhary, J. N. Derr Journal of Mammalogy, 85(5):924-931, 2004 Presented by Caitlin Pyle

  2. The American Bison (Bos bison) • The American bison is endemic to North America, once ranging from Canada to Northern Mexico • They are gregarious animals, whom are predominately grazers • From 1877-1878 • There were 1,500 hunting outfits working out of just Shackelford County • More than 100,000 hides were taken in the months of December-January

  3. www.llanoestacado.org

  4. Two subspecies of Bison Plains bison are what we are familiar with in the old American Prairies. Wood bison lived in Canada, and were forest animals Nationalgeographic.com

  5. It all started withThe Goodnight Herd • In the mid-1880s Charles Goodnight, a Texas rancher along with his wife, Molly, founded the Goodnight herd from 5 wild-caught bison • The population peaked in the 1920s with 200-250 bison • After Goodnight’s death in 1929 the herd switched hands many times www.nature.com

  6. Meet the official Texas State Bison Herd • By 1970 the population was down between 40-100 bison • In 1997, the remaining 36 bison were donated to Texas Parks and Wildlife (TPWD) and renamed Texas State Bison Herd (TSBH) • TPWD relocated the bison to the Caprock Canyon State Park (CCSP) in the Texas panhandle www.llanoestacado.org

  7. Anew beginning atCaprock Canyon State Park • CCSP is 320 acres of grazing land of Indian grass and sideoatsgramma • Supplemented with native hay • The herd receives annual vaccinations • Free of any common ungulate diseases • Given daily visual inspections tpwd.state.tx.us

  8. The CCSP Bison suffer from • Low natality rates (birth rates) • High calf mortality • In 2000, 8 bulls were fertility tested with ½ of them exhibiting sperm abnormalities • In 2003, 18 females were pregnancy tested, 15 were pregnant, 5 calves were born, yet only 1 survived tpwd.state.tx.us

  9. Objectives of the Study • Expand the microsatellite panel of the Bison • including the 29 autosomal genes along with sex chromosomes • Goal was to assess the genetic variability of the bison • Compare the TSBH to the Yellowstone National Park (YSNP) and the Theodore Roosevelt National Park (TRNP) • Karyotype the individuals of the TSBH

  10. Study Sites Theodore Roosevelt State Park in North Dakota Caprock Canyon State Parkin Texas Yellowstone National Park in Wyoming adventuremedianews.com nps.gov tpwd.state.tx.us

  11. Materials and MethodsSample Collections • TSBH- Blood and tail hair samples from 19 males and 21 females in 2001 • Metaphase chromosome spreads were obtained using the standard colcemid and hypotonic technique • TRNP-Blood samples from 100 bison in 2000 • YSNP-Liver samples from 100 deceased bison between 1996-2001 Karger.com

  12. Materials and MethodsMarker Choice and Multiplexing • Chose 54 unlinked bovine microsatellite loci using USDA gene mapping database • Had at least 1 marker per chromosome • Used Genotyper 3.6 software for allele identification and comparison. Rosalind.info

  13. Materials and MethodsData Analysis • Used program CERVUS 2.0 with analysis parameters of • 10,000 cycles • 1% genotyping error rate • 80% relaxed confidence • 95% strict confidence • Used program GENEPOP 3.1 to evaluate • Hardy-Weinberg equilibrium • Heterozygosity • Number of alleles/locus for all 54 locus tested within the Markov parameters • 10,000 step dememorization • 125 bathes • 40,000 iterations per batch All comparisons between populations of average hetereozygosityand alleles used standard unpaired t-test with P< 0.0001

  14. Materials and MethodsPopulation Viability • Using VORTEX 8.42 • 100 year simulation • 10,000 iterations • Polygynous breeding with 10% of males (based on parentage data) • No density dependence • No correlation between survival or breeding variation from environmental conditions • Assumed standard deviation of 5% • Inbreeding within default parameters was used

  15. ResultsData analysis • Metaphase chromosomes preparations • Collected 29 of the 31 TSBH bison • All had normal karyotypes • Bison have 60 chromosomes • Of the 54 nuclear microsatellites • 8 monomorphic loci in the TSBH • 1 amongst the other bison populations • Of the 46 polymorphic autosomal loci • 3 significantly deviated from H-W expectations (P < 0.05)

  16. Results The average number of alleles per locus and heterezygosity in the TSBH was significantly lower(p<0.0001) in comparison to the other two herds.

  17. ResultsPopulation Viability • First Evaluation Probability of extinction of the TSBH in the next 100 years including inbreeding was • O.9997 ±0.0002 SE • With an average year of 40.59 ±0.13 years • Second Evaluation Probability of extinction of the TSBH in the next 100 years excluding inbreeding was • 0.9812 ±0.0014 SE • With an average year of 45.71 ±0.17 years

  18. DiscussionUnique alleles • There were 9 alleles found only in the TSBH in comparison with the other two bison herds • 8 of these alleles have been previously reported in domestic cattle or bison • ILSTS102 allele was unique to the TSBH

  19. DiscussionNe Formula of Lande and Barrowclough • If all the adults from the TSBH are considered: • The population= 24 (10 M, 15 F) • Using this formula results in an effective population of 13.3 • Lower than the minimum recommended short term population size of 50

  20. DiscussionGenetic Drift • In the TSBH there is a 6.8% difference in the number of alleles between the adult population and the current calf population born between 1998-2001 • The TSBH has been living in isolation for 160 years with a chronic low population, and several bottleneck episodes genetic drift will continue to negatively effect genetic diversity.

  21. Discussion The future • Even with intensive management over the TSBH, there is a 99% likelihood that they will go extinct in the next 41 years due to • Genetic Drift • Multiple bottlenecks and low population • Low hetereozygosity • Low natality rates • Sperm abnormalities • Inbreeding • The only optionfor the TSBH would be to sacrifice the closed population, and bring new bison into the TSBH. This would introduce new alleles into the population.

  22. In class portionFrom Chapter 11 • American bison are charismatic megafauna • 50-500 Rule, Minimum viable population • Inbreeding depression • Low genetic diversity • Low polymorphic alleles • Genetic drift • Bottleneck effect • National Park protected area Level 2 • Bison form aggregations, have a large body size, require a large home range, and have little genetic variability, all of these are closely linked with extinction. • Locally extinct • Ecologically extinct • Similar story to the lions of Ngorongro with the small closed population that suffers from low genetic diversity and genetic drift

  23. Literature Cited HalbertN. D., T. Raudsepp, B. P. Chowdhary, J. N. Derr; Conservation Genetic Analysis of the Texas State Bison HerdJournal of Mammalogy, 85(5):924-931, 2004 Schmidly, D. J. 1994. The Mammals of Texas. Print Primack R. B. 2010. Essentials of Conservation Biology. Print. Fiedler, P. L. Kareiva, P. M. 1998. Conservation Biology: For the coming Decade. Print

  24. QUESTIONS?

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