Ecological genetics of the moss Physcomitrella patens

Molecular genetic studies using the model bryophyte Physcomitrella patens have advanced the body of knowledge surrounding plant functional genetics and molecular biology, yet very little is known about the ecology and population genetics of this species. Although the bryophytes are the second largest group of
plants, there is little information regarding the population genetics of bryophytes in general. To address these issues I have conducted the first study into the population genetics of P. patens, where plants from eight populations in Britain have been collected. Sampling within these populations was conducted according to a hierarchical scale, so as to assess not only the level of genetic variation within populations, but how this is structured spatially. Analysis of the plants collected was conducted using amplified fragment length polymorphism (AFLP) analysis. No spatial genetic structure was found within populations of P. patens, and it is hypothesised that the nature of the ephemeral aquatic habitats that P. patens occupies may account for this finding. In this thesis a novel method for studying the mating systems operating within bryophyte populations has been proposed, which exploits the dominant haploid stage of the bryophyte life cycle. This methodology has been applied to natural populations of P. patens, and evidence of mixed mating has been observed. Bryophytes are often overlooked
or under-recorded in their natural environment, and distribution data within Great Britain is likely to be
inaccurate for a large number of species. This issue is highlighted in this thesis, as a bryophyte species new to Europe has been discovered.