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Australian Journal of Botany Australian Journal of Botany Society
Southern hemisphere botanical ecosystems
RESEARCH ARTICLE

Genetic diversity and biogeography of the boab Adansonia gregorii (Malvaceae: Bombacoideae)

Karen L. Bell A B E , Haripriya Rangan B , Rachael Fowler A B , Christian A. Kull B , J. D. Pettigrew C , Claudia E. Vickers D and Daniel J. Murphy A
+ Author Affiliations
- Author Affiliations

A Royal Botanic Gardens Melbourne, Birdwood Avenue, South Yarra, Vic. 3141, Australia.

B School of Geography and Environmental Science, Monash University, Clayton, Vic. 3800, Australia.

C Queensland Brain Institute, University of Queensland, St Lucia, Qld 4072, Australia.

D Australian Institute for Bioengineering and Nanotechnology, University of Queensland, St Lucia, Qld 4072, Australia.

E Corresponding author. Email: karen.bell@monash.edu

Australian Journal of Botany 62(2) 164-174 https://doi.org/10.1071/BT13209
Submitted: 23 August 2013  Accepted: 12 April 2014   Published: 22 May 2014

Abstract

The Kimberley region of Western Australia is recognised for its high biodiversity and many endemic species, including the charismatic boab tree, Adansonia gregorii F.Muell. (Malvaceae: Bombacoideae). In order to assess the effects of biogeographic barriers on A. gregorii, we examined the genetic diversity and population structure of the tree species across its range in the Kimberley and adjacent areas to the east. Genetic variation at six microsatellite loci in 220 individuals from the entire species range was examined. Five weakly divergent populations, separated by west–east and coast–inland divides, were distinguished using spatial principal components analysis. However, the predominant pattern was low geographic structure and high gene flow. Coalescent analysis detected a population bottleneck and significant gene flow across these inferred biogeographic divides. Climate cycles and coastline changes following the last glacial maximum are implicated in decreases in ancient A. gregorii population size. Of all the potential gene flow vectors, various macropod species and humans are the most likely.

Additional keywords: Australian monsoon tropics, baobab, dispersal, gene flow, genetic admixture, Kimberley, microsatellite, phylogeography.


References

Armstrong P (1979) The history, natural history and distribution of Adansonia: a plant genus of the Indian Ocean littoral. In ‘The Indian Ocean in focus. International conference on Indian Ocean studies, Perth, Western Australia 1979. Section I. Environment and resources’. (Ed. P Reeves) pp. 1–21. (Perth Building Society: Perth)

Armstrong P (1983) The disjunct distribution of the genus Adansonia L. The National Geographical Journal of India 29, 142–163.

Assogbadjo AE, Glele Kakai R, Kyndt T, Sinsin B (2010) Conservation genetics of baobab (Adansonia digitata L.) in the parklands agroforestry systems of Benin (West Africa). Notulae Botanicae Horti Agrobotanici Cluj-Napoca 38, 136–140.

Australian Government Department of Sustainability, Environment, Water, Population and Communities (2012) ‘IBRA version 7.’ (Canberra)

Balzarini M, Teich I, Bruno C, Peña A (2011) Making genetic biodiversity measurable: a review of statistical multivariate methods to study variability at gene level. Revista de la Facultad de Ciencias Agrarias 43, 261–275.

Baum DA (1995a) The comparative pollination and floral biology of baobabs (Adansonia – Bombacaceae). Annals of the Missouri Botanical Garden 82, 322–348.
The comparative pollination and floral biology of baobabs (Adansonia – Bombacaceae).Crossref | GoogleScholarGoogle Scholar |

Baum DA (1995b) A systematic revision of Adansonia (Bombacaceae). Annals of the Missouri Botanical Garden 82, 440–471.
A systematic revision of Adansonia (Bombacaceae).Crossref | GoogleScholarGoogle Scholar |

Baum DA, Handasyde T (1990) The boab tree (Adansonia gregorii) in north-west Australia. Unpublished report in Western Australian Herbarium Library, Perth.

Baum DA, Small RL, Wendel JF (1998) Biogeography and floral evolution of baobabs (Adansonia, Bombacaceae) as inferred from multiple data sets. Systematic Biology 47, 181–207.
Biogeography and floral evolution of baobabs (Adansonia, Bombacaceae) as inferred from multiple data sets.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD38zitVKrug%3D%3D&md5=c5dca5e45c7c1e7212e9e12245134804CAS | 12064226PubMed |

Beard JS (1967) Some vegetation types of tropical Australia in relation to those of Africa and America. Journal of Ecology 55, 271–290.
Some vegetation types of tropical Australia in relation to those of Africa and America.Crossref | GoogleScholarGoogle Scholar |

Beerli P (2006) Comparison of Bayesian and maximum likelihood inference of population genetic parameters. Bioinformatics 22, 341–345.
Comparison of Bayesian and maximum likelihood inference of population genetic parameters.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28XhtFaisbo%3D&md5=b5bc1cd66233b5ce04c9c38ba0b11b6cCAS | 16317072PubMed |

Beerli P (2009) How to use migrate or why are markov chain monte carlo programs difficult to use? In ‘Population genetics for animal conservation’. (Eds G Bertorelle, MW Bruford, HC Hauffe, A Rizzoli, C Vernesi) pp. 42–79. (Cambridge University Press: Cambridge, UK)

Beerli P, Felsenstein J (2001) Maximum likelihood estimation of a migration matrix and effective population sizes in n subpopulations by using a coalescent approach. Proceedings of the National Academy of Sciences, USA 98, 4563–4568.
Maximum likelihood estimation of a migration matrix and effective population sizes in n subpopulations by using a coalescent approach.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3MXjtVagtLY%3D&md5=c0d80834c9030bac418aef0ec4690fbbCAS |

Boland DJ, Brooker MIH, Chippendale GM, Hall N, Hyland BPM, Johnston RD, Kleinig DA, Turner JD (1985) ‘Forest trees of Australia.’ 4th edn. (Nelson and CSIRO: Melbourne)

Bowman DMJS (1997) Observations on the demography of the Australian boab (Adansonia gibbosa) in the north-west of the Northern Territory, Australia. Australian Journal of Botany 45, 893–904.
Observations on the demography of the Australian boab (Adansonia gibbosa) in the north-west of the Northern Territory, Australia.Crossref | GoogleScholarGoogle Scholar |

Bowman DMJS, Brown GK, Braby MF, Brown JR, Cook LG, Crisp MD, Ford F, Haberle P, Hughes J, Isagi Y, Joseph L, McBride J, Nelson G, Ladiges PY (2010) Biogeography of the Australian monsoon tropics. Journal of Biogeography 37, 201–216.
Biogeography of the Australian monsoon tropics.Crossref | GoogleScholarGoogle Scholar |

Brock J (1988) ‘Top End native plants.’ (Brock: Darwin)

Brummitt RK (2002) A consideration of ‘Nomina Subnuda’. Taxon 51, 171–174.
A consideration of ‘Nomina Subnuda’.Crossref | GoogleScholarGoogle Scholar |

Byrne M, Yeates DK, Joseph L, Kearney M, Bowler J, Williams MAJ, Cooper Byrne M, Yeates DK, Joseph L, Kearney M, Bowler J, Williams MAJ, Cooper (2008) Birth of a biome: insights into the assembly and maintenance of the Australian arid zone biota. Molecular Ecology 17, 4398–4417.
Birth of a biome: insights into the assembly and maintenance of the Australian arid zone biota.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD1cjhvFGruw%3D%3D&md5=18e1e5ae25a7438fbd76312775e9fb69CAS | 18761619PubMed |

Chen C, Durand E, Forbes F, François O (2007) Bayesian clustering algorithms ascertaining spatial population structure: a new computer program and comparison study. Molecular Ecology Notes 7, 747–756.
Bayesian clustering algorithms ascertaining spatial population structure: a new computer program and comparison study.Crossref | GoogleScholarGoogle Scholar |

Clark PU, Dyke AS, Shakun JD, Carlson AE, Clark J, Wohlfarth B, Mitrovica JX, Hostetler SW, McCabe AM (2009) The Last Glacial Maximum. Science 325, 710–714.
The Last Glacial Maximum.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXptl2gu7g%3D&md5=e05af54f0979ddab8067e4a3e660f64aCAS | 19661421PubMed |

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

Cunningham A (1827) Natural history appendix. In ‘Narrative of a survey of the intertropical and western coasts of Australia performed between the years 1818 and 1822’. (Ed. PP King) pp. 408–629. (John Murray: London)

Duvall CS (2007) Human settlement and baobab distribution in south-western Mali. Journal of Biogeography 34, 1947–1961.
Human settlement and baobab distribution in south-western Mali.Crossref | GoogleScholarGoogle Scholar |

Earl DA, von Holdt BM (2012) STRUCTURE HARVESTER: a website and program for visualizing STRUCTURE output and implementing the Evanno method. Conservation Genetics Resources 4, 359–361.
STRUCTURE HARVESTER: a website and program for visualizing STRUCTURE output and implementing the Evanno method.Crossref | GoogleScholarGoogle Scholar |

Eldridge MDB, Potter S, Cooper SJB (2011) Biogeographic barriers in north-western Australia: an overview and standardisation of nomenclature. Australian Journal of Zoology 59, 270–272.
Biogeographic barriers in north-western Australia: an overview and standardisation of nomenclature.Crossref | GoogleScholarGoogle Scholar |

Estoup A, Jarne P, Cornuet J-M (2002) Homoplasy and mutation model at microsatellite loci and their consequences for population genetics analysis. Molecular Ecology 11, 1591–1604.
Homoplasy and mutation model at microsatellite loci and their consequences for population genetics analysis.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38XnvVWhsLg%3D&md5=9bf5e9e0d2afcb96d6158b596546a9f3CAS | 12207711PubMed |

Evanno G, Regnaut S, Goudet J (2005) Detecting the number of clusters of individuals using the software STRUCTURE: a simulation study. Molecular Ecology 14, 2611–2620.
Detecting the number of clusters of individuals using the software STRUCTURE: a simulation study.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXmvF2qtrg%3D&md5=9768cb9d92ec62dae4e93a84977410f8CAS | 15969739PubMed |

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.

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.

François O, Ancelet S, Guillot G (2006) Bayesian clustering using hidden Markov random fields in spatial population genetics. Genetics 174, 805–816.
Bayesian clustering using hidden Markov random fields in spatial population genetics.Crossref | GoogleScholarGoogle Scholar | 16888334PubMed |

Gillison AN (1983) Tropical savannas of Australia and southwest Pacific. In ‘Tropical savannas. Vol. 13’. (Ed. F Bourliere) pp. 183–243. (Elsevier Scientific Publishing: Amsterdam)

Hey J, Nielsen R (2004) Multilocus methods for estimating population sizes, migration rates and divergence time, with applications to the divergence of Drosophila pseudoobscura and D. persimilis. Genetics 167, 747–760.
Multilocus methods for estimating population sizes, migration rates and divergence time, with applications to the divergence of Drosophila pseudoobscura and D. persimilis.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXms1KntL8%3D&md5=806bb1ab4e726bec0a180102bfadabfbCAS | 15238526PubMed |

Hill KD, Johnson LAS (1995) Systematic studies in the eucalypts. 7. A revision of the bloodwoods, genus Corymbia (Myrtaceae). Telopea 6, 185–504.

Jakobsson M, Rosenberg NA (2007) CLUMPP: a cluster matching and permutation program for dealing with label switching and multimodality in analysis of population structure. Bioinformatics 23, 1801–1806.
CLUMPP: a cluster matching and permutation program for dealing with label switching and multimodality in analysis of population structure.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXpt1ahtbs%3D&md5=8ee17ac13abf31e1c79922b4db068da5CAS | 17485429PubMed |

James EA, Brown GK, Citroen R, Rossetto M, Porter C (2011) Development of microsatellite loci in Triglochin procera (Juncaginaceae), a polyploid wetland plant. Conservation Genetics Resources 3, 103–105.
Development of microsatellite loci in Triglochin procera (Juncaginaceae), a polyploid wetland plant.Crossref | GoogleScholarGoogle Scholar |

Jombart T, Devillard S, Dufour A-B, Pontier D (2008) Revealing cryptic spatial patterns in genetic variability by a new multivariate method. Heredity 101, 92–103.
Revealing cryptic spatial patterns in genetic variability by a new multivariate method.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXnt1eis7g%3D&md5=89f40977b9de6dc27a62d1165d24a9aaCAS | 18446182PubMed |

Kershaw P (1995) Environmental change in Greater Australia. Antiquity 69, 656–675.

Larsen AS, Vaillant A, Verhaegen D, Kjær ED (2009) Eighteen SSR-primers for tetraploid Adansonia digitata and its relatives. Conservation Genetics Resources 1, 325–328.
Eighteen SSR-primers for tetraploid Adansonia digitata and its relatives.Crossref | GoogleScholarGoogle Scholar |

Lowe P (1998) ‘The boab tree.’ (Lothian Books: Melbourne)

Luikart G, Allendorf F, Cornuet J-M, Sherwin W (1998) Distortion of allele frequency distributions provides a test for recent population bottlenecks. The Journal of Heredity 89, 238–247.
Distortion of allele frequency distributions provides a test for recent population bottlenecks.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaK1czitVKhsA%3D%3D&md5=fdb96eeefd090cdf998847eb8d559bcdCAS | 9656466PubMed |

McConnell K, O’Connor S (1997) 40,000 year record of food plants in the Southern Kimberley Ranges, Western Australia. Australian Archaeology 45, 20–31.

McConnell K, O’Connor S (1999) Carpenter’s Gap shelter I: a case for total recovery. In ‘Taphonomy: the analysis of processes from phytoliths to megafauna’. (Eds MJ Mountain, D Bowdery) pp. 23–34. (ANH Publications: Canberra)

Melville J, Ritchie EG, Chapple SNJ, Glor RE, Schulte JA (2011) Evolutionary origins and diversification of dragon lizards in Australia’s tropical savannas. Molecular Phylogenetics and Evolution 58, 257–270.
Evolutionary origins and diversification of dragon lizards in Australia’s tropical savannas.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC3M3gtV2htg%3D%3D&md5=5885684a856aa0814d7e3132be26dc09CAS | 21145401PubMed |

Meirmans PG (2012) The trouble with isolation by distance. Molecular Ecology 21, 2839–2846.
The trouble with isolation by distance.Crossref | GoogleScholarGoogle Scholar | 22574758PubMed |

Mueller F von (1857) New genera and species. Hooker’s journal of botany and Kew Garden miscellany 9, 14.

Mueller F von (1858) Botanical report on the North Australian exploring expedition. Proceedings of the Linnean Society of London (Botany) 2, 140–149.

Mueller F von (1893) Botanical notes from north-west Australia. Victorian Naturalist 10, 110–111.

Oliver PM, Adams M, Doughty P (2010) Molecular evidence for ten species and Oligo–Miocene vicariance within a nominal Australian gecko species (Crenadactylus ocellatus, Diplodactylidae). BMC Evolutionary Biology 10, 386
Molecular evidence for ten species and Oligo–Miocene vicariance within a nominal Australian gecko species (Crenadactylus ocellatus, Diplodactylidae).Crossref | GoogleScholarGoogle Scholar | 21156080PubMed |

Peakall R, Smouse PE (2006) GENALEX 6: genetic analysis in Excel. Population genetic software for teaching and research. Molecular Ecology Notes 6, 288–295.
GENALEX 6: genetic analysis in Excel. Population genetic software for teaching and research.Crossref | GoogleScholarGoogle Scholar |

Pettigrew J (2011) Iconography in Bradshaw rock art: breaking the circularity. Clinical & Experimental Optometry 94, 403–417.
Iconography in Bradshaw rock art: breaking the circularity.Crossref | GoogleScholarGoogle Scholar |

Pettigrew JD, Bell KL, Bhagwandin A, Grinan E, Jillani N, Meyer J, Wabuyele E, Vickers CE (2012) Morphology, ploidy and molecular phylogenetics reveal a new diploid species from Africa in the baobab genus Adansonia (Bombacoideae; Malvaceae). Taxon 61, 1240–1250.

Potter S, Eldridge MDB, Cooper SJB, Paplinska JZ, Taggart DA (2012a) Habitat connectivity, more than species’ biology, influences genetic differentiation in a habitat specialist, the short-eared rock-wallaby (Petrogale brachyotis). Conservation Genetics 13, 937–952.
Habitat connectivity, more than species’ biology, influences genetic differentiation in a habitat specialist, the short-eared rock-wallaby (Petrogale brachyotis).Crossref | GoogleScholarGoogle Scholar |

Potter S, Eldridge MDB, Taggart DA, Cooper SJB (2012b) Multiple biogeographical barriers identified across the monsoon tropics of northern Australia: phylogeographic analysis of the brachyotis group of rock-wallabies. Molecular Ecology 21, 2254–2269.
Multiple biogeographical barriers identified across the monsoon tropics of northern Australia: phylogeographic analysis of the brachyotis group of rock-wallabies.Crossref | GoogleScholarGoogle Scholar | 22417115PubMed |

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

R Development Core Team (2008) ‘R: a language and environment for statistical computing.’ (R foundation for Statistical Computing: Vienna)

Raven PH, Axelrod DI (1974) Angiosperm biogeography and past continental movements. Annals of the Missouri Botanical Garden 61, 539–673.
Angiosperm biogeography and past continental movements.Crossref | GoogleScholarGoogle Scholar |

Rosenberg NA (2004) DISTRUCT: a program for the graphical display of population structure. Molecular Ecology Notes 4, 137–138.
DISTRUCT: a program for the graphical display of population structure.Crossref | GoogleScholarGoogle Scholar |

Shaw J, Lickey EB, Schilling EE, Small RL (2007) Comparison of whole chloroplast genome sequences to choose noncoding regions for phylogenetic studies in angiosperms: the tortoise and the hare III. American Journal of Botany 94, 275–288.
Comparison of whole chloroplast genome sequences to choose noncoding regions for phylogenetic studies in angiosperms: the tortoise and the hare III.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXktFOjsLg%3D&md5=bf6d48c52970d764849447d39b56e480CAS | 21636401PubMed |

Sun JX, Mullikin JC, Patterson N, Reich DE (2009) Microsatellites are molecular clocks that support accurate inferences about history. Molecular Biology and Evolution 26, 1017–1027.
Microsatellites are molecular clocks that support accurate inferences about history.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXkslGlu7Y%3D&md5=a66c0762fc67bea290d2b077e8aa9f2cCAS | 19221007PubMed |

Thuillet A-C, Bru D, David J, Roumet P, Santoni S, Sourdille P, Bataillon T (2002) Direct estimation of mutation rate for 10 microsatellite loci in durum wheat, Triticum turgidum (L.) Thell. ssp. durum desf. Molecular Biology and Evolution 19, 122–125.
Direct estimation of mutation rate for 10 microsatellite loci in durum wheat, Triticum turgidum (L.) Thell. ssp. durum desf.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38XhtFChsg%3D%3D&md5=c0d300d7f3c8222aab6947a98148eb32CAS | 11752198PubMed |

Wallis LA (2001) Environmental history of northwest Australia based on phytolith analysis at Carpenter’s Gap 1. Quaternary International 83–85, 103–117.
Environmental history of northwest Australia based on phytolith analysis at Carpenter’s Gap 1.Crossref | GoogleScholarGoogle Scholar |

Wickens GE (1982) The baobab: Africa’s upside-down tree. Kew Bulletin 37, 173–209.
The baobab: Africa’s upside-down tree.Crossref | GoogleScholarGoogle Scholar |

Wickens GE, Lowe P (2008) ‘The baobabs: pachycauls of Africa, Madagascar, and Australia.’ (Springer: Berlin)