Skip to main content

Advertisement

Log in

How much is enough? Minimum sampling intensity required to capture extant genetic diversity in ex situ seed collections: examples from the endangered plant Sibara filifolia (Brassicaceae)

  • Research Article
  • Published:
Conservation Genetics Aims and scope Submit manuscript

Abstract

Sibara filifolia (Brassicaceae), Santa Cruz Island Rock Cress, an endangered annual plant endemic to the California Channel Islands which was presumed extinct for nearly 50 years, is currently known from only a few small patches on San Clemente Island (SCl) and Santa Catalina Island (SCa). In addition to protecting extant populations, recovery efforts have included ex situ seed collections to hedge against stochastic population losses. We examined genetic diversity and population structure in the wild and the effect of sampling intensity on the genetic diversity of ex situ seed collections using 13 species-specific microsatellite loci. Much of the genetic variation on each island consisted of rare alleles; 33 % (SCl) or 56 % (SCa) of the non-fixed alleles occurred at frequencies ≤0.05. Patches on SCl were genetically depauperate (mean HO = 0.002) compared to patches on SCa (mean HO = 0.344). One patch on SCl was genetically distinct, while the remaining four patches were genetically indistinguishable. The three patches on SCa were genetically distinct from those on SCl, but not from one another. Simulated sampling for the ex situ seed collections found that 10 individuals was sufficient to capture 90 % of the diversity for normalized measures (NE, HO, and HE) in a depauperate (SCl) population, while 30 individuals was necessary in a diverse (SCa) population. However, sampling 125 (SCl) or 60 (SCa) individuals was necessary to capture 90 % of all the alleles present. These findings indicate that theoretical guidelines for ex situ seed collections that recommend targeting 50 individuals per population overestimate the sampling effort required to adequately preserve common alleles, but may underestimate the effort necessary to capture most alleles in wild populations.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5

Similar content being viewed by others

References

  • Allendorf FW (1986) Genetic drift and the loss of alleles versus heterozygosity. Zool Biol 5:181–190

    Article  Google Scholar 

  • Brown AHD, Briggs JD (1991) Sampling strategies for genetic variation in ex situ collections of endangered plant species. In: Falk DA, Holsinger KE (eds) Genetics and conservation of rare plants. Oxford University Press, New York, pp 99–119

    Google Scholar 

  • Bureau of Land Management (2012) Technical protocol for the collection, study, and conservation of seeds from native plant species for seeds of success, Washington, D.C. http://www.nps.gov/plants/sos/index.htm. Accessed Dec 2013

  • Cornuet JM, Luikart G (1996) Description and power analysis of two tests for detecting recent population bottlenecks from allele frequency data. Genetics 144:2001–2014

    PubMed Central  CAS  PubMed  Google Scholar 

  • CPC (Center for Plant Conservation) (2010) Sibara filifolia. Center for Plant Conservation. http://www.centerforplantconservation.org/Collection/CPC_ViewProfile.asp?CPCNum=3953. Accessed 1 Oct 2012

  • Da Silva A, Gaillard JM, Yoccoz NG, Hewison AJM, Galan M, Coulson T, Allaine D, Vial L, Delorme D, Van Laere G, Klein F, Luikart G (2009) Heterozygosity-fitness correlations revealed by neutral and candidate gene markers in roe deer from a long-term study. Evolution 63:403–417

    Article  PubMed  Google Scholar 

  • Di Rienzo A, Peterson AC, Garza JC, Valdes AM, Slatkin M, Freimer N (1994) Mutational processes of simple sequence repeat loci in human population. Proc Natl Acad Sci USA 91:3166–3170

    Article  PubMed Central  PubMed  Google Scholar 

  • Earl DA, Vonholdt BM (2012) STRUCTURE HARVESTER: a website and program for visualizing STRUCTURE output and implementing the Evanno method. Conserv Genet Resour 4:359–361

    Article  Google Scholar 

  • Evanno G, Regnaut S, Goudet J (2005) Detecting the number of clusters of individuals using the software STRUCTURE: a simulation study. Mol Ecol 14:2611–2620

    Article  CAS  PubMed  Google Scholar 

  • Excoffier L, Smouse PE, Quattro JM (1992) Analysis of molecular variance inferred from metric distances among DNA haplotypes: application to human mitochondrial DNA restriction data. Genetics 131:479–491

    PubMed Central  CAS  PubMed  Google Scholar 

  • Excoffier L, Laval G, Schneider S (2005) Arlequin ver. 3.0: an integrated software package for population genetics data analysis. Evol Bioinform Online 1:47–50

    PubMed Central  CAS  Google Scholar 

  • Falush D, Stephens M, Pritchard JK (2003) Inference of population structure using multilocus genotype data: linked loci and correlated allele frequencies. Genetics 164:1567–1587

    PubMed Central  CAS  PubMed  Google Scholar 

  • Furches MS, Wallace LE, Helenurm K (2009) High genetic divergence characterizes populations of the endemic plant Lithophragma maximum (Saxifragaceae) on San Clemente Island. Conserv Genet 10:115–126

    Article  Google Scholar 

  • Gao H, Williamson S, Bustamante CD (2007) A Markov chain Monte Carlo approach for joint inference of population structure and inbreeding rates from multilocus genotype data. Genetics 176:1635–1651

    Article  PubMed Central  PubMed  Google Scholar 

  • Gapare WJ, Yanchuk AD, Aitken SN (2007) Optimal sampling strategies for capture of genetic diversity differ between core and peripheral populations of Picea sitchensis (Bong.) Carr. Conserv Genet 9:411–418

    Article  Google Scholar 

  • Godefroid S, Vyver A, Vanderborght T (2009) Germination capacity and viability of threatened species collections in seed banks. Biodivers Conserv 19:1365–1383

    Article  Google Scholar 

  • Guerrant EO, Fiedler PL, Havens K, Maunder M (2004a) Revised genetic sampling guidelines for conservation collections of rare and endangered plants. In: Guerrant EO, Havens K, Maunder M (eds) Ex situ plant conservation: supporting species survival in the wild. Island Press, Washington, DC, pp 419–438

    Google Scholar 

  • Guerrant EO, Havens K, Maunder M (2004b) Ex situ plant conservation: supporting species survival in the wild. Island Press, Washington, DC

    Google Scholar 

  • Helenurm K (2003) Genetic diversity in the rare insular endemic Sibara filifolia (Brassicaceae). Madrono 50:181–186

    Google Scholar 

  • Henry RJ (2006) Plant conservation genetics. Food Products Press, New York

    Google Scholar 

  • Hubisz MJ, Falush D, Stephens M, Pritchard JK (2009) Inferring weak population structure with the assistance of sample group information. Mol Ecol Resour 9:1322–1332

    Article  PubMed Central  PubMed  Google Scholar 

  • Jump AS, Marchant R, Penuelas J (2009) Environmental change and the option value of genetic diversity. Trends Plant Sci 14:51–58

    Article  CAS  PubMed  Google Scholar 

  • Knopp T, Cano JM, Crochet PA, Merila J (2007) Contrasting levels of variation in neutral and quantitative genetic loci on island populations of moor frogs (Rana arvalis). Conserv Genet 8:45–56

    Article  Google Scholar 

  • Lauretto MS, Nakano F, Faria SR, Pereira CAB, Stern JM (2009) A straightforward multiallelic significance test for the Hardy–Weinberg equilibrium law. Genet Mol Biol 32:619–625

    Article  PubMed Central  PubMed  Google Scholar 

  • Lawrence MJ (2002) A comprehensive collection and regeneration strategy for ex situ conservation. Genet Resour Crop Evol 49:199–209

    Article  Google Scholar 

  • Lawrence MJ, Marshall DF, Davies P (1995) Genetics of genetic conservation. I. Sample size when collecting germplasm. Euphytica 84:89–99

    Article  Google Scholar 

  • Leinonen T, O’hara RB, Cano JM, Merila J (2008) Comparative studies of quantitative trait and neutral marker divergence: a meta-analysis. J Evolution Biol 21:1–17

    CAS  Google Scholar 

  • Li DZ, Pritchard HW (2009) The science and economics of ex situ plant conservation. Trends Plant Sci 14:614–621

    Article  CAS  PubMed  Google Scholar 

  • Lockwood DR, Richards CM, Volk GM (2007) Probabilistic models for collecting genetic diversity: comparisons, caveats, and limitations. Crop Sci 47:861–868

    Article  Google Scholar 

  • Luikart G, Cornuet JM (1998) Empirical evaluation of a test for identifying recently bottlenecked populations from allele frequency data. Conserv Biol 12:228–237

    Article  Google Scholar 

  • Marshall DR, Brown AHD (1975) Optimum sampling strategies in genetic conservation. In: Frankel OH, Hawkes JG (eds) Crop genetic resources for today and tomorrow. Cambridge University Press, Cambridge Eng.; New York, pp 53–80

    Google Scholar 

  • McGlaughlin ME, Wallace LE, Helenurm K (2008) Isolation of microsatellite loci from the endangered plant Sibara filifolia (Brassicaceae). Mol Ecol Resour 8:367–369

    Article  CAS  PubMed  Google Scholar 

  • McGlaughlin ME, Wallace LE, Wheeler GL, Bresowar G, Riley L, Britten NR, Helenurm K (2014) Do the island biogeography predictions of MacArthur and Wilson hold when examining genetic diversity on the near mainland California Channel Islands? Examples from endemic Acmispon (Fabaceae). Bot J Linn Soc 174:289–304

    Article  Google Scholar 

  • Neel MC, Cummings MP (2003) Effectiveness of conservation targets in capturing genetic diversity. Conserv Biol 17:219–229

    Article  Google Scholar 

  • Nybom H (2004) Comparison of different nuclear DNA markers for estimating intraspecific genetic diversity in plants. Mol Ecol 13:1143–1155

    Article  CAS  PubMed  Google Scholar 

  • Ouborg NJ, Pertoldi C, Loeschcke V, Bijlsma R, Hedrick PW (2010) Conservation genetics in transition to conservation genomics. Trends Genet 26:177–187

    Article  CAS  PubMed  Google Scholar 

  • Peakall R, Smouse PE (2012) GenAlEx 6.5: genetic analysis in Excel. Population genetic software for teaching and research—an update. Bioinformatics 28:2537–2539

    Article  PubMed Central  CAS  PubMed  Google Scholar 

  • Piry S, Luikart G, Cornuet JM (1999) BOTTLENECK: a computer programme for detecting recent reductions in the effective population size using allele frequency data. J Hered 90:502–503

    Article  Google Scholar 

  • Pritchard JK, Stephens M, Donnelly P (2000) Inference of population structure using multilocus genotype data. Genetics 155:945–959

    PubMed Central  CAS  PubMed  Google Scholar 

  • Raymond M, Rousset F (1995) Genepop (version-1.2)—population-genetics software for exact tests and ecumenicism. J Hered 86:248–249

    Google Scholar 

  • Reed DH, Frankham R (2001) How closely correlated are molecular and quantitative measures of genetic variation? A meta-analysis. Evolution 55:1095–1103

    Article  CAS  PubMed  Google Scholar 

  • Reed DH, Frankham R (2003) Correlation between fitness and genetic diversity. Conserv Biol 17:230–237

    Article  Google Scholar 

  • Richards CM, Lockwood DR, Volk GM, Walters C (2010) modeling demographics and genetic diversity in ex situ collections during seed storage and regeneration. Crop Sci 50:2440

    Article  Google Scholar 

  • Riley L, McGlaughlin ME, Helenurm K (2010) Genetic diversity following demographic recovery in the insular endemic plant Galium catalinense subspecies acrispum. Conserv Genet 11:2015–2025

    Article  Google Scholar 

  • Rust R, Menke A, Miller D (1985) A biogeographic comparison of the bees, sphecid wasps, and mealybugs of the California Channel Islands (Hymenoptera, Homoptera). In: Miller D, Menke A (eds.) Entomology of the California Channel Islands: proceedings of the first symposium, Santa Barbara Museum of Natural History, Santa Barbara, California, pp 29–59

  • Schaal B, Leverich WJ (2004) Population genetic issues in ex situ plant conservation. In: Guerrant EO, Havens K, Maunder M (eds) Ex situ plant conservation: supporting species survival in the wild. Island Press, Washington, DC, pp 267–285

    Google Scholar 

  • Schoen DJ, Brown AHD (2001) The conservation of wild plant species in seed banks. Bioscience 51:960–966

    Article  Google Scholar 

  • Secretariat of the Convention on Biological Diversity (2009) The convention on biological diversity plant conservation report: a review of progress in implementing the global strategy of plant conservation (GSPC). Secretariat of the Convention on Biological Diversity, Montreal

    Google Scholar 

  • USFWS (1997) Determination of endangered status for three plants from the Channel Islands of southern California. Fed Reg 62:42692–42702

    Google Scholar 

  • USFWS (2012) Sibara filifolia (Santa Cruz Island rock-cress) 5-year review: summary and evaluation. (ed. USFWS Carlsbad Fish and Wildlife Office C, CA), http://ecos.fws.gov/speciesProfile/profile/speciesProfile.action?spcode=Q1OF

  • Wallace LE, Helenurm K (2009) Has herbivory negatively impacted genetic variability in the flora of the California Channel Islands? Insights from Crossosoma Californicum (Crossosomataceae). Int J Plant Sci 170:311–322

    Article  Google Scholar 

  • Walters C (2004) Principles for preserving germplasm in gene banks. In: Guerrant EO, Havens K, Maunder M (eds) Ex situ plant conservation: supporting species survival in the wild. Island Press, Washington, DC, pp 113–138

    Google Scholar 

Download references

Acknowledgments

This research was funded by the Natural Resource Office, Staff Civil Engineer, Naval Air Station, North Island, San Diego, California, and the University of Northern Colorado. The Catalina Island Conservancy generously provided access and logistical support for all sampling conducted on Santa Catalina Island. We would like to thank two anonymous reviewers for comments on earlier versions of this paper.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Mitchell E. McGlaughlin.

Electronic supplementary material

Below is the link to the electronic supplementary material.

Supplementary material 1 (DOCX 88 kb)

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

McGlaughlin, M.E., Riley, L., Brandsrud, M. et al. How much is enough? Minimum sampling intensity required to capture extant genetic diversity in ex situ seed collections: examples from the endangered plant Sibara filifolia (Brassicaceae). Conserv Genet 16, 253–266 (2015). https://doi.org/10.1007/s10592-014-0655-3

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10592-014-0655-3

Keywords

Navigation