Conservation Genetics

, Volume 9, Issue 2, pp 411–418 | Cite as

Optimal sampling strategies for capture of genetic diversity differ between core and peripheral populations of Picea sitchensis (Bong.) Carr

  • Washington J. Gapare
  • Alvin D. Yanchuk
  • Sally N. Aitken
Research Article

Abstract

In previous studies we reported that while core populations of Sitka spruce [Picea sitchensis (Bong.) Carr] have little within-population genetic structure, peripheral populations are strongly spatially structured at distances up to 500 m. Here we explore the implications of this difference in structure on ex situ gene conservation collections and estimates of genetic diversity from research collections. We test the effects of varying the number of individuals sampled and the total area they are sampled across on capture of neutral genetic variation in collections from core, continuous versus peripheral, disjunct populations. Bivariate response surface analysis of genetic marker data for eight sequence tagged site loci from core and peripheral populations suggest that a population sample from 150 trees covering at least 225 ha would be adequate for capturing 95% of the genetic diversity (as measured by allelic richness or expected heterozygosity) in core populations. However, a larger sample of 180 individuals from an area of at least 324 ha is needed in peripheral populations to capture the same proportion of standing variation because of stronger within-population spatial genetic structure. Standard population sampling protocols for estimating among and within-population genetic diversity would significantly underestimate the within-population allelic richness and expected heterozygosity of peripheral but not core populations, potentially leading to poor representation of genetic variation in peripheral populations as well as erroneous conclusions about their genetic impoverishment.

Keywords

Genetic diversity Core populations Peripheral populations Sampling strategies Ex situ gene conservation 

References

  1. Batista F, Banares A, Caujape-Castells J, Marrero-Gomez M, Carque E, Sosa PA (2001) Allozyme diversity in three endemic species of Cistus (Cistaceae) from the Canary islands: Intraspecific and interspecific comparisons and implications for genetic conservation. Am J Bot 88:1582–1592CrossRefGoogle Scholar
  2. Brown ADH, Marshall DR (1995) A basic sampling strategy: theory and practice. In: Guarino L, Ramantha Rao VR (eds) Collecting plant genetic diversity: technical guidelines. CAB International, Wallington, UK, pp. 75–111Google Scholar
  3. Buchert GP, Rajora OP, Hood JV, Dancik BP (1997) Effects of harvesting on genetic diversity in old-growth eastern white pine in Ontario, Canada. Conserv Biol 11:747–758CrossRefGoogle Scholar
  4. Bush RM, Smouse P (1992) Evidence of adaptive significance of allozymes in forest trees. New For 6:179–96Google Scholar
  5. Doyle JJ, Doyle JL (1990) Isolation of plant DNA from fresh tissue. Focus 23:13–15Google Scholar
  6. FAO (2004) Establishment and management of ex situ conservation stands. For Genet Res Inf 20:7–10Google Scholar
  7. Frankel OH, Soulė ME (1981) Conservation and evolution. Cambridge University Press, Cambridge, p. 327Google Scholar
  8. Gapare WJ (2003) Genetic diversity and spatial population structure of Sitka spruce (Picea sitchensis (Bong.)Carr.): implications for gene conservation of widespread species. Ph.D. thesis, University of British Columbia, p. 148Google Scholar
  9. Gapare WJ, Aitken SN (2005) Strong spatial genetic structure in peripheral but not core populations of Sitka spruce (Picea sitchensis (Bong.)Carr.). Mol Ecol 14:2659–2667PubMedCrossRefGoogle Scholar
  10. Gapare WJ, Aitken SN, Ritland CE (2005) Genetic diversity of core and peripheral Sitka spruce (Picea sitchensis (Bong.)Carr.) populations: implications for gene conservation of widespread species. Biol Conserv 123:113–123CrossRefGoogle Scholar
  11. Gilmour AR, Gogel BJ, Cullis BR, Welham SJ, Thompson R. (2005) ASReml User Guide Release 2.0, VSN International Ltd., Hemel Hempstead HP1 1ES, UKGoogle Scholar
  12. Hamrick JL, Godt MJW, Murawski DA, Loveless MD (1991) Correlations between species traits and allozyme diversity: implications for conservation biology. In: Falk DA, Holsinger K (eds) Genetics and conservation of rare plants. Oxford University Press, New York, pp.75–86Google Scholar
  13. Hartl DL, Clark GC (1997) Principles of population genetics, 3rd edn. Sinauer Associates Inc. Publishers, Sunderland, MA, pp. 542Google Scholar
  14. Johnson R, St. Clair B, Lipow S (2001) Genetic conservation in applied tree breeding programs. In: Proceedings international conference on ex situ and in situ conservation of commercial tropical trees. Yogyakarta, IndonesiaGoogle Scholar
  15. Kimura M, Crow JF (1964) The number of alleles that can be maintained in a finite population. Genetics 49:725–38PubMedGoogle Scholar
  16. Lawrence MJ, Marshall DF, Davies P (1995) Genetics of genetic conservation I. Sample size when collecting germplasm. Euphytica 84:89–99CrossRefGoogle Scholar
  17. Ledig FT, Bermejo-Velazquez PD, Hodgskiss DR, Johnson C, Flores-Lopez, Jacob-Cervantes V (2000) The mating system and genetic diversity in Martinez spruce, an extremely rare endemic of Mexico’s Sierra Madre Oriental: an example of facultative selfing and survival in interglacial refugia. Can J For Res 30:1156–1164CrossRefGoogle Scholar
  18. Lewis PO, Zaykin D (2001) Genetic data analysis: computer program for the analysis of allelic data. Version 1.0 (d16c). Free program distributed by the authors over the internet: Citied http://lewis.eeb.uconn.edu/lewishome/software.htmlGoogle Scholar
  19. Lowe A, Harris S, Ashton P (2005) Ecological genetics: design, analysis, and application. Blackwell Publishing, VIC, Australia, pp. 326Google Scholar
  20. Marshall DR, Brown ADH (1975) Optimum sampling strategies for gene conservation. In: H. Frankel O, Hawkes JG (eds) Crop genetic resources for today and tomorrow. Cambridge University Press, Cambridge, London, pp 53–80Google Scholar
  21. Millar CI, Westfall RD (1992) Allozyme markers in forest genetic conservation. New For 6:347–371Google Scholar
  22. Muller-Starck G (1995) Genetic variation in high elevation populations of Norway spruce (Picea abies [L.] Karst.) in Switzerland. Silvae Genet 44:356–362Google Scholar
  23. Namkoong G (1988) Sampling for germplasm collections. Hortscience 23:79–81Google Scholar
  24. Nei M (1978) Estimation of average heterozygosity and genetic distance from a small number of individuals. Genetics 89:583–590PubMedGoogle Scholar
  25. Nei M, Maruyama T, Charkraborty R (1975) The bottleneck effect and genetic variability in populations. Evolution 29:1–10CrossRefGoogle Scholar
  26. Parker KC, Hamrick JL, ParkerAJ, Nason JD (2001) Fine-scale genetic structure in Pinus clausa (Pinaceae) populations: effects of disturbance history. Heredity 87:99–113PubMedCrossRefGoogle Scholar
  27. Perry DJ, Bousquet J (1998a) Sequence-tagged-site (STS) markers of arbitrary genes: Development, characterization and analysis of linkage in black spruce. Genetics 149:1089–1098PubMedGoogle Scholar
  28. Perry DJ, Bousquet J (1998b) Sequence-tagged-site (STS) markers of arbitrary genes: the utility of black spruce-derived STS primers in other conifers. Theor Appl Genet 97:735–743CrossRefGoogle Scholar
  29. Petit RJ, El-Mousadik A, Pons O (1998) Identifying populations for conservation on the basis of genetic markers. Conserv Biol 12:844–855CrossRefGoogle Scholar
  30. Rawlings JO, Pantula SG, Dickey DA (1998) Applied regression analysis: a research tool, 2nd edn. Springer, New York, pp 657Google Scholar
  31. Ritland K, Jain S (1981) Model for the estimation of outcrossing rate and gene frequencies using n independent loci. Heredity 47:35–52CrossRefGoogle Scholar
  32. SAS Institute Inc. (1999) SAS/STAT User’s Guide, version 8, SAS online documentation. SAS Institute Inc., Cary, NC, USAGoogle Scholar
  33. Schoen DJ, Brown ADH (1991) Intraspecific variation in gene diversity and effective population size correlated with the mating system in plants. Proc Nat Acad Sci USA 88:4494–4497PubMedCrossRefGoogle Scholar
  34. Sproule AT, Dancik BP (1996) The mating system of black spruce in north-Alberta, Canada. Silvae Genet 45:159–164Google Scholar
  35. Stoehr MU, El-Kassaby YA (1997) Levels of genetic diversity at different stages of the domestication cycle of interior spruce in British Columbia. Theor Appl Genet 94:83–90CrossRefGoogle Scholar
  36. Theilade I (2003) The role of ex situ conservation of trees in living stands. Guidelines and technical notes No. 64. Danida Forest Seed Centre, Hunlebaek, DenmarkGoogle Scholar
  37. Yanchuk AD (2001) A quantitative framework for breeding and conservation of forest tree genetic resources in British Columbia. Can J For Res 31:566–576CrossRefGoogle Scholar
  38. Vekemans X, Hardy OJ (2004) New insights from fine-scale spatial genetic structure analyses in plant populations. Mol Ecol 13:921–935PubMedCrossRefGoogle Scholar
  39. Young AG, Brown ADH, Zich FA (1999) Genetic structure of fragmented populations of the Endangered Daisy Rutidosis leptorrhynchoides. Conserv Biol 13:256–265CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2007

Authors and Affiliations

  • Washington J. Gapare
    • 1
    • 3
  • Alvin D. Yanchuk
    • 2
  • Sally N. Aitken
    • 1
  1. 1.Centre for Forest Gene ConservationUniversity of British ColumbiaVancouverCanada
  2. 2.Ministry of Forests, Research Branch, British ColumbiaVictoriaCanada
  3. 3.Ensis (Ensis is a joint venture between CSIRO FFP P/L and SCION Australasia P/L), CSIRO Forestry and Forest ProductsKingstonAustralia

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