Global distribution and molecular diversity of Didymium difforme

Abstract

Fifty-six collections of Didymium difforme from three different geographically distant regions of the world were examined for intraspecific variation using DNA sequences. An approximately 400 base pair region of the mitochondrial small subunit was sequenced for each collection. The analysis of the sequences did not resolve the collections from each geographic region into separate groups. Instead, all but one of the six major groups included sequences from collections originating in at least two different regions. The one group with sequences from one region (Kenya) to the exclusion of the other two regions was made up of sequences from collections made at different localities within the region. Other sequences from the same localities were, however, found in the other major groups most closely related to sequences from the other two regions.