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School of Biological and Chemical Sciences

Leif Bersweden


PhD student



Project title: Species integrity and gene flow in anthropomorphic Orchis species

Summary: The British anthropomorphic species of Orchis (O. anthropophora, O. militaris, O. purpurea and O. simia) hybridize readily when they co-occur, both in England and mainland Europe. Some of the resulting hybrids appear to be evolutionary dead ends whereas others back-cross in one or both directions, giving rise to forms with differing degrees of introgression. Preliminary data show that at least some populations that appear morphologically to be pure species are in fact introgressed forms. To complicate the issue further, O. purpurea appears to include two distinct genetic lineages (equivalent to species), although no morphological differences have so far been detected. Next generation sequencing technologies now provide the opportunity to tease relationships among these species apart in far greater detail and to characterize patterns of hybridization. Results with lead to 1) a greater understanding of what constitutes species coherence in this group, 2) improved understanding of patterns of hybridization and 3) better informed conservation management.