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Prof. John Pannell

My research is directed towards understanding

  1. the evolution of plant gender, sexual dimorphism and sex allocation strategies;
  2. the ecology, genetics and evolution of polyploidy, especially in its interaction with the sexual system;
  3. the evolution of local adaptation, particularly in colonizing plant species; and
  4. the ecology and population genetics of metapopulations subject to repeated local extinctions and re-colonisations.

Curriculum vitae

Professor in Plant Evolution, University of Lausanne

Lecturer, Reader and Professor in Plant Evolutionary Biology, University of Oxford

Postdoc with Brian and Deborah Charlesworth, University of Edinburgh, UK

Postdoc with Spencer Barrett, University of Toronto, Canada

Doctoral studies at the University of Oxford, supervised by Alan Grafen

Research Officer, Forestry Commission, Tasmania, Australia

BSc, University of Sydney, Australia

Current projects

Testing models of sex allocation in subdivided populations
How should individuals divide their limited reproductive resources between the production and dispersal of pollen versus seeds when they occur in a fragmented population? We are currently addressing this question from a theoretical perspective through the construction of evolutionarily stable strategy (ESS) and quantitative genetic models of sex allocation for metapopulations, in which local populations are subject to dramatic fluctuations in their size, including extinction and colonisation events. The predictions made by this theory are being tested using the plant Mercurialis annua as a model system. This species shows remarkable variation in its sexual system in Europe, especially in the , where dioecious (the co-occurrence of males and females), monoecious (functional hermaphrodites) and androdioecious populations (the co-occurrence of males with hermaphrodites) are all widespread in different regions.

A spatially hierarchical analysis of the role of colonisation in plant metapopulations
Annual plant populations are notoriously patchy. Whether these patches should usefully be regarded as subpopulations or not is a largely operational question. However, the way in which patches become established, become extinct, or coalesce into a continuous population by expansion into one another can have a profound influence on the amount and patterns of genetic diversity maintained within a species. We are currently assessing the extent to which patches within spatially extended populations are spatially coherent, particularly with a view towards understanding why many self-fertilising annual plant populations maintain much less variation than one would expect on the basis of species-wide diversity.

The genetic and ecological significance of cryptic females in dioecious species
In dioecious species, it is usually only the males that produce pollen. However, several species in a range of different families are known in which males and ‘hermaphrodites’ occur at a ratio of 1:1. Species with even sex ratios must be functionally dioecious, and simple theory tells us that the apparent pollen producing ‘hermaphrodites’ are functioning only as females. We are interested in the functional significance of pollen produced by functional females in the Mediterranean species Fraxinus ornus. Collaborator Miguel Verdú, Valencia, Spain.

The evolution of local adaptation in colonising plants
Colonising plants, like all organisms, are expected to become locally adapted to their environments as a response to natural selection. They are particularly interesting for at least two reasons. First, colonising species that are new arrivals in a region will be potentially subject to strong selection in their new environment and might be expected to show rapid responses to this selection. And second, their morphology, life history and physiology is expected to respond to natural selection not only locally, but also to selective forces acting at regional level during the process of colonising itself. Selection at the regional or metapopulation level is thus particularly likely to shape dispersal-related traits, including the mating system.

The evolution and ecology of secondary sexual dimorphism in plants
Many dioecious species show dimorphism not only in their sex allocation and floral structures, but also in vegetative traits, with males and females often differing in their morphology and architecture, physiology and life history. Secondary sexual divergence has been much studied in animals, but our understanding of the underlying selective forces in plants are poorly understood. We are interested in how much of this variation is the result of sexual selection (or selective agents analogous to sexual selection), and how much a result of selection on the different reproductive roles carried out by males and females, with their divergent costs and benefits?

The evolution of plant-plant signalling strategies for gender determination
Because plants are sessile, their success depends critically on an ability to respond plastically to changes in their environment. For example, they respond to light quality, day length, soil nutrient availability, herbivory, etc. Such responses typically maximise growth and survivorship in a given context, but to what extent is phenotypic plasticity used to maximise mating and reproductive success? In many animal species, individuals are known to modify their morphology and behaviour in response to local mating opportunities. We are considering the possibility plants, too, might have evolved a similar ability to switch gender in response to perceived opportunities, given that mating success in plants also depends on local mate availability.

The evolution of sex-determination mechanisms
The gender of organisms with separate sexes can be determined be a range of environmental and genetic mechanisms. We are interested in why, and to what degree, plants have evolved aspects of environmental sex determination and environment-dependent sex allocation. We are also interested in the implications of genetic sex determination for the molecular evolution of the underlying loci, and those loci linked to them. Here, we are using as empirical models both the clade of annual Mercurialis species, with its remarkable diversity of sexual systems in which separate sexes have evolved more than once (collaborator: Dmitry Filatov), as well the freshwater crustacean Eulimnadia texana, in which self-fertilization by hermaphrodites evidently produces genotypes that express deleterious alleles linked to the sex-determining locus.

2015 |  2014 |  2013 |  2012 |  2011 |  2010 |  2009 |  2008 |  2007 |  2006 |  2005 |  2004 |  2003 |  2002 |  2001 |  2000 |  1999 |  1997 |  1993 | 

Pannell J.R., 2015. Evolution of the mating system in colonizing plants. Molecular Ecology . [DOI] [Pubmed]
Roux C., Pannell J.R., 2015. Inferring the mode of origin of polyploid species from next-generation sequence data. Molecular Ecology 24(5) pp. 1047-1059. [DOI] [Web of Science] [Pubmed]
Pannell J.R., 2014. Leaf Mimicry: Chameleon-like Leaves in a Patagonian Vine. Current Biology 24(9) pp. R357-R359. [DOI] [Web of Science] [Pubmed]
Pannell J.R., Eppley S.M., Dorken M.E., Berjano R., 2014. Regional variation in sex ratios and sex allocation in androdioecious Mercurialis annua. Journal of Evolutionary Biology 27(7) pp. 1467-1477. [DOI] [Web of Science] [Pubmed]
Pujol B., Marrot P., Pannell J.R., 2014. A quantitative genetic signature of senescence in a short-lived perennial plant. Current Biology 24(7) pp. 744-747. [DOI] [Web of Science] [Pubmed]
Pannell J.R., Fields P.D., 2013. Evolution in subdivided plant populations: concepts, recent advances and future directions. New Phytologist 201(2) pp. 417-432. [DOI] [Web of Science] [Pubmed]
Pannell J.R., Labouche A.M., 2013. The incidence and selection of multiple mating in plants. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences 368(1613) p. 20120051. [DOI] [Web of Science] [Pubmed]
Pannell J.R., 2012. Speciation genetics: reinforcement by shades and hues. Current Biology 22(9) pp. R299-R302. [DOI] [Web of Science] [Pubmed]
Pannell J.R., 2012. The ecology of plant populations: their dynamics, interactions and evolution. Annals of Botany 110(7) pp. 1351-1355. [DOI] [Web of Science]
Sanchez Vilas J., Pannell J.R., 2012. Do plants adjust their sex allocation and secondary sexual morphology in response to their neighbours? Annals of Botany 110(7) pp. 1471-1478. [DOI] [Web of Science] [Pubmed]
Santos-del-Blanco L., Climent J., González-Martínez S.C., Pannell J.R., 2012. Genetic differentiation for size at first reproduction through male versus female functions in the widespread Mediterranean tree Pinus pinaster. Annals of Botany 110(7) pp. 1449-1460. [DOI] [Web of Science] [Pubmed]
Hesse E, Pannell J.R., 2011. Sexual dimorphism in androdioecious Mercurialis annua, a wind-pollinated herb. International Journal of Plant Sciences 172(1) pp. 49-59. [DOI] [Web of Science]
Moore J.C., Pannell J.R., 2011. Sexual selection in plants. Current Biology 21(5) pp. R176-R182. [DOI] [Web of Science] [Pubmed]
Pfeiffer T., Roschanski A.M., Pannell J.R., Korbecka G., Schnittler M., 2011. Characterization of microsatellite loci and reliable genotyping in a polyploid plant, Mercurialis perennis (Euphorbiaceae). Journal of Heredity 102(4) pp. 479-488. [DOI] [Web of Science] [Pubmed]
Sánchez Vilas J., Pannell J.R., 2011. Sex-differential herbivory in androdioecious Mercurialis annua. PLoS One 6(7) pp. e22083. [DOI] [Web of Science] [Pubmed]
Sánchez Vilas J., Pannell J.R., 2011. Sexual dimorphism in resource acquisition and deployment: both size and timing matter. Annals of Botany 107(1) pp. 119-126. [DOI] [Web of Science] [Pubmed]
Harris M.S., Pannell J.R., 2010. Canopy seed storage is associated with sexual dimorphism in the woody dioecious genus Leucadendron. Journal of Ecology 98(2) pp. 509-515. [DOI] [Web of Science]
Pannell J.R., Korbecka G., 2010. Mating-system evolution: rise of the irresistible males. Current Biology 20(11) pp. R482-R484. [DOI] [Web of Science] [Pubmed]
Pujol B, Obbard D.J, Pannell J.R., 2010. Symptoms of population range expansion: lessons from phenotypic and genetic differentiation in hexaploid Mercurialis annua. Plant Ecology and Diversity 3(2) pp. 103-108. [DOI] [Web of Science]
Sánchez-Vilas J., Pannell J.R., 2010. Differential niche modification by males and females of a dioecious herb: extending the Jack Sprat effect. Journal of Evolutionary Biology 23(10) pp. 2262-2266. [DOI] [Web of Science] [Pubmed]
Zhou S., Zhou C., Pannell J.R., 2010. Genetic load, inbreeding depression and heterosis in an age-structured metapopulation. Journal of Evolutionary Biology 23(11) pp. 2324-2332. [DOI] [Web of Science] [Pubmed]
Zhou S.R., Pannell J.R., 2010. Inbreeding depression and genetic load at partially linked loci in a metapopulation. Genetics Research 92(2) pp. 127-140. [DOI] [Web of Science] [Pubmed]
Bernasconi G., Antonovics J., Biere A., Charlesworth D., Delph L.F., Filatov D., Giraud T., Hood M.E., Marais G.A., McCauley D. et al., 2009. Silene as a model system in ecology and evolution. Heredity 103(1) pp. 5-14. [DOI] [Web of Science] [Pubmed]
Dorken M.E., Pannell J.R., 2009. Hermaphroditic sex allocation evolves when mating opportunities change. Current Biology 19(6) pp. 514-517. [DOI] [Web of Science] [Pubmed]
Harris S.R., Henbest K.B., Maeda K., Pannell J.R., Timmel C.R., Hore P.J., Okamoto H., 2009. Effect of magnetic fields on cryptochrome-dependent responses in Arabidopsis thaliana. Journal of the Royal Society, Interface 6(41) pp. 1193-1205. [DOI] [Web of Science] [Pubmed]
Pannell J.R, Pujol B., 2009. The paradoxical spread of a new Y chromosome - a novel explanation. Trends in Ecology and Evolution 24(2) pp. 59-63. [DOI] [Web of Science]
Pannell J.R., 2009. Mating-system evolution: genies from a bottleneck. Current Biology 19(9) pp. R369-R370. [DOI] [Web of Science] [Pubmed]
Pannell J.R., 2009. Mating-system evolution: succeeding by celibacy. Current Biology 19(21) pp. R983-R985. [DOI] [Web of Science] [Pubmed]
Pannell J.R., 2009. On the problems of a closed marriage: celebrating Darwin 200. Biology Letters 5(3) pp. 332-335. [DOI] [Web of Science] [Pubmed]
Pujol B., Zhou S.R., Sanchez Vilas J., Pannell J.R., 2009. Reduced inbreeding depression after species range expansion. Proceedings of the National Academy of Sciences of the United States of America 106(36) pp. 15379-15383. [DOI] [Web of Science] [Pubmed]
Dorken M.E., Pannell J.R., 2008. Density-dependent regulation of the sex ratio in an annual plant. American Naturalist 171(6) pp. 824-830. [DOI] [Web of Science] [Pubmed]
Gleiser G., Segarra-Moragues J.G., Pannell J.R., Verdú M., 2008. Siring success and paternal effects in heterodichogamous Acer opalus. Annals of Botany 101(7) pp. 1017-1026. [DOI] [Web of Science] [Pubmed]
Gleiser G., Verdú M., Segarra-Moragues J.G., González-Martínez S.C., Pannell J.R., 2008. Disassortative mating, sexual specialization, and the evolution of gender dimorphism in heterodichogamous Acer opalus. Evolution 62(7) pp. 1676-1688. [DOI] [Web of Science] [Pubmed]
Harris M.S., Pannell J.R., 2008. Roots, shoots and reproduction: sexual dimorphism in size and costs of reproductive allocation in an annual herb. Proceedings of the Royal Society B Biological Sciences 275(1651) pp. 2595-2602. [DOI] [Web of Science] [Pubmed]
Pannell J.R., Dorken M.E., Pujol B., Berjano R., 2008. Gender variation and transitions between sexual systems in Mercurialis annua (Euphorbiaceae). International Journal of Plant Sciences 169(1) pp. 129-139. [DOI] [Web of Science]
Pujol B., Pannell J.R., 2008. Reduced responses to selection after species range expansion. Science 321(5885) p. 96. [DOI] [Web of Science] [Pubmed]
Pujol B., Wilson A.J., Ross R.I., Pannell J.R., 2008. Are Q(ST)-F(ST) comparisons for natural populations meaningful? Molecular Ecology 17(22) pp. 4782-4785. [DOI] [Web of Science] [Pubmed]
Dorken M.E., Pannell J.R., 2007. The maintenance of hybrid zones across a disturbance gradient. Heredity 99(1) pp. 89-101. [DOI] [Web of Science] [Pubmed]
Pannell J.R., 2007. Dispersal ecology: where have all the seeds gone? Current Biology 17(10) pp. R360-R362. [DOI] [Web of Science] [Pubmed]
Obbard D.J, Pannell J.R, Harris S.A., 2006. Mercurialis canariensis (Euphorbiaceae), a new endemic to the Canary Islands. Kew Bulletin 61(1) pp. 99-106. [url editor site]
Obbard D.J., Harris S.A., Buggs R.J., Pannell J.R., 2006. Hybridization, polyploidy, and the evolution of sexual systems in Mercurialis (Euphorbiaceae). Evolution 60(9) pp. 1801-1815. [DOI] [Web of Science] [Pubmed]
Obbard D.J., Harris S.A., Pannell J.R., 2006. Sexual systems and population genetic structure in an annual plant: testing the metapopulation model. American Naturalist 167(3) pp. 354-366. [DOI] [Web of Science] [Pubmed]
Obbard D.J., Harris S.A., Pannell J.R., 2006. Simple allelic-phenotype diversity and differentiation statistics for allopolyploids. Heredity 97(4) pp. 296-303. [DOI] [Web of Science] [Pubmed]
Verdú M., González-Martínez S.C., Montilla A.I., Mateu I., Pannell J.R., 2006. Ovule discounting in an outcrossing, cryptically dioecious tree. Evolution 60(10) pp. 2056-2063. [DOI] [Web of Science] [Pubmed]
Pannell J.R., Dorken M.E., Eppley S.M., 2005. 'Haldane's Sieve' in a metapopulation: sifting through plant reproductive polymorphisms. Trends in Ecology and Evolution 20(7) pp. 374-379. [DOI] [Web of Science] [Pubmed]
Pannell J.R, Obbard D.J, Buggs R.J.A., 2004. Polyploidy and the sexual system: what can we learn from Mercurialis annua? Biological Journal of the Linnean Society 82(4) pp. 547-560. [DOI] [Web of Science]
Pannell J.R., Eppley S.M., 2004. Intraorganismal genetic heterogeneity: is it a useful concept? Journal of Evolutionary Biology 17(6) pp. 1180-1; discussion 1192-4. [DOI] [Web of Science] [Pubmed]
Verdú M., Montilla A.I., Pannell J.R., 2004. Paternal effects on functional gender account for cryptic dioecy in a perennial plant. Proceedings of the Royal Society of London B Biological Sciences 271(1552) pp. 2017-2023. [DOI] [Web of Science] [Pubmed]
López-Almansa J.C., Pannell J.R., Gil L., 2003. Female sterility in Ulmus minor (Ulmaceae): a hypothesis invoking the cost of sex in a clonal plant. American Journal of Botany 90(4) pp. 603-609. [DOI] [Web of Science] [Pubmed]
Pannell J.R, Obbard D.J., 2003. Probing the primacy of the patch: what makes a metapopulation? Journal of Ecology 91(3) pp. 485-488. [DOI] [Web of Science]
Pannell J.R., 2002. The evolution and maintenance of androdioecy. Annual Review of Ecology and Systematics 33 pp. 397-425. [DOI] [Web of Science]
Pannell J.R., 2002. What is functional androdioecy? Functional Ecology 16(6) pp. 862-865. [DOI] [Web of Science]
Pannell J.R., Barrett S.C., 2001. Effects of population size and metapopulation dynamics on a mating-system polymorphism. Theoretical Population Biology 59(2) pp. 145-155. [DOI] [Web of Science] [Pubmed]
Pannell J.R., 2000. Evolution in subdivided populations. Trends in Ecology and Evolution 15(3) pp. 90-92. [DOI] [Web of Science]
Pannell J.R., Charlesworth B., 2000. Effects of metapopulation processes on measures of genetic diversity. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences 355(1404) pp. 1851-1864. [DOI] [Web of Science] [Pubmed]
Pannell J., 1997. Widespread functional androdioecy in Mercurialis annua L. (Euphorbiaceae). Biological Journal of the Linnean Society 61(1) pp. 95-116. [DOI] [Web of Science]
Pannell J.R, Myerscough P.J., 1993. Canopy-stored seed banks of Allocasuarina distyla and A. nana in relation to time since fire Australian. Australian Journal of Botany 41(1) pp. 1-9. [DOI] [Web of Science]


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