Population Genetics of UK Orchids

Due to the rarity of many species, UK orchids are a main focus of activity for Kew’s Conservation Genetics Group.

Orchis militaris.

Of the approximately 50 species of orchids native to the UK, many are rare, and some of them spectacularly so. For example, Cypripedium calceolus was reduced to a single plant, largely due to over collection in the 20th Century, and Epipogium aphyllum was refound in 2009 after having not been seen in the UK since 1986. As a result of this high level of rarity and the high profile of many orchids in documents such as Schedule 8 of the Wildlife and Countryside Act 1981 (12 species and two subspecies are listed), orchids have formed a major focus for Kew’s Conservation Genetics Group (part of the Genetics Section) since its establishment in the mid 1990s.

Projects are chosen in close collaboration with the statutory conservation agencies, notably Natural England, and the taxa are targeted as ones for which genetic data will have a clear application in deciding management strategies. Questions relate to variation within and between populations, confirmation of native status of cultivated plants, identification of hybrids etc. Subjects for study include Cephalanthera longifolia, Cephalanthera rubra, Cypripedium calceolus, Dactylorhiza species, Ophrys fuciflora, Ophrys sphegodes, Orchis militaris, Orchis purpurea and Orchis simia. Results from our studies are fed back to the relevant agency/agencies in the form of conservation genetics reports, with recommendations for management changes in light of the genetic data when appropriate. Studies are also published in peer-reviewed journals as appropriate.

Vinogradov (2003) demonstrated a strong correlation with genome size and rarity (as expressed as IUCN categories), with species with larger genomes tending to be rarer than those with small genomes. This is reflected in the range of species worked on in this project as species of Cephalanthera, Cypripedium, Ophrys and Orchis all have large to very large genomes. However, the large genome sizes cause problems with standard fingerprinting techniques, notably AFLP (amplified fragment length polymorphism) and nuclear microsatellites, which are often compromised or ineffective in taxa with large genomes. We are therefore investigating the use of other markers to use with these species where appropriate.

Key publication 2006-2011

• Paun, O., Bateman, R. M., Fay, M. F., Luna J. A., Moat, J., Hedrén, M. & Chase, M. W. (2011). Altered gene expression and ecological divergence in sibling allopolyploids of Dactylorhiza (Orchidaceae). BMC Evolutionary Biology 11: 113 (doi:10.1186/1471-2148-11-113).
• Micheneau, C., Duffy, K. J., Smith, R. J., Stevens L. J., Stout, J. C., Civeyrel, L., Cowan, R. S. & Fay, M. F. (2010). Plastid microsatellites for the study of genetic variability in the widespread Cephalanthera longifolia, C. damasonium and C. rubra (Neottieae, Orchidaceae), and cross amplification in other Cephalanthera species. Botanical Journal of the Linnean Society 163: 181-193.
• Fay, M. F., Bone, R., Cook, P., Kahandawala, I., Greensmith, J., Harris, S., Pedersen, H. Æ., Ingrouille, M. J. & Lexer, C. (2009). Genetic diversity in Cypripedium calceolus (Orchidaceae) with a focus on northwestern Europe, as revealed by plastid DNA length polymorphisms. Annals of Botany 104: 517-525.
• Bateman, R. M., Smith R. J. & Fay, M. F. (2008). Morphometric and population genetic analyses elucidate the origin, evolutionary significance and conservation implications of Orchis ´angusticruris (O. purpurea ´ O. simia.), a hybrid orchid new to Britain. Botanical Journal of the Linnean Society 157: 687–711.
• Devey, D. S., Bateman, R. M., Fay, M. F. & Hawkins, J. A. (2008). Friends or relatives? Phylogenetics and species delimitation in the controversial European orchid genus Ophrys. Annals of Botany 101: 385-402.