Conservation of genetic diversity in British populations of the diploid endemic Coincya monensis ssp monensis (Isle of Man Cabbage): the risk of hybridisation with the tetraploid alien, Coincya monensis ssp cheiranthos |
| |
Authors: | Paul D Facey Patricia L M Lee Melvin N E Smith and Charles R Hipkin |
| |
Institution: | (1) Biological Sciences, Institute of Environmental Sustainability, School of the Environment and Society, University of Wales Swansea, South Wales, UK, SA2 8PP |
| |
Abstract: | Coincya monensis is represented in the British flora by two, cytologically distinct subspecies. Coincya monensis ssp monensis is an endemic diploid with a coastal sand dune distribution that includes a number of isolated populations. Coincya monensis ssp cheiranthos is a tetraploid alien, well established in South Wales in early successional habitats. Both subspecies share similar life
form traits, flowering times and pollinators. Cluster analysis and phylogenetic reconstruction based on sequences of the mitochondrial
nad4 gene confirmed the distinction between alien and endemic taxa. Tetraploid populations carry more polymorphic RAPDs loci and
their genetic diversity is partitioned more within than among populations. In contrast, C. monensis ssp monensis has a distinct population genetic structure. Analysis of the multilocus genetic data confirmed a structure of genetically
isolated, endemic population clusters in Scotland, Arran, the Isle of Man and South Wales. Experimental hybridisation showed
the two subspecies are interfertile. Multivariate analysis of RAPDs data resolved hybrids between alien and endemic clusters
and hybrids contained a proportion of alien-specific polymorphic loci. Hybrids of alien maternal parentage contained the mitochondrial
nad4 sequence characteristic of the alien subspecies. Since the alien subspecies can invade mobile sand dune communities from
urban sites and compete for pollinators, there is a risk that alien and endemic populations will mix and introgress. Conservation
of endemic genetic diversity in Britain will require protection for all C. monensis ssp monensis populations. Currently, the most disjunct endemic population in South Wales is most at risk from introgression. |
| |
Keywords: | Alien Coincya monensis Endemic Hybridisation Population structure Phylogenetic relationship |
本文献已被 SpringerLink 等数据库收录! |
|