Tracking genotypic changes in Paramecium isolates between ponds and seasons in Ulster County, NY

Abstract

The numerous species of Paramecia can vary morphologically, functionally, and genetically. Previous biogeographical studies of Paramecium suggest that the cells follow the ‘everything is everywhere’ hypothesis and that local ecology determines the particular strains found in any given location. However, there has not been much research done on strain and species changes from season to season over short geographical distances as well as if or how Paramecia overwinter under ice. Over seven consecutive seasons, we have sampled five local ponds for Paramecium cells. We isolated single cells, created lines of culture and allowed them to grow to high density from each collected sample. We then extracted DNA, amplified specific genes by polymerase chain reaction (PCR), and sequenced them by Sanger sequencing. To determine the species, we compared the new sequences to sequences of known Paramecium species. Overall, it was found that there is species and haplotype diversity within and between ponds. For Paramecium caudatum there is a more dominant haplotype for all of the sampled ponds. However, for Paramecium aurelia there is more diversity and there are species that are only pond in certain ponds. Additionally, we were able to retrieve samples, albeit a small number, containing Paramecium cells from under the ice in a completely frozen lake suggesting that Paramecia may overwinter in this region.