Genomic analysis of Irish bog butter

Abstract The deposition of butter in bogs is well documented in the archaeological record, from prehistoric to post-medieval times. To our knowledge this pilot study presents the first genetic analysis of bog butter, using technological advances that demonstrate the ability to reveal new information from substrates previously untested for genetic data. In this analysis, DNA was successfully isolated from three Irish bog butter samples using a novel approach. Furthermore, high throughput shotgun DNA sequencing was successful and bovine DNA sequences were recovered from all three samples of bog butter. Investigation of the environmental DNA (metagenomic analysis) recovered from the bog butter samples clearly identified similarities between samples taken from the same bog butter. This pilot analysis suggests that bog butter could be used as a substrate for DNA extraction, thereby furthering our understanding of diet and animal use in the past.