Ancient DNA from Ascaris: extraction amplification and sequences from eggs collected in coprolites

Abstract

On the Middle-Age site of Namur (Belgium) the analysis of coprolites revealed the presence of many well-preserved Ascaris eggs. Following rehydratation of the coprolite samples, 104 eggs were collected and extracted with an ultrasonication and phenol-chloroform based method. Three overlapping fragments of the 18S rRNA gene and one fragment of the cytochrome b gene have been reproducibly amplified, cloned and sequenced. The analysis of these sequences confirms the identification of the eggs as coming from Ascaris. Our study reveals that coprolites can be an interesting source of parasites that can be readily identified using molecular approaches. The study of ancient DNA from helminth parasites is of interest as it may answer long-standing questions in the history of infectious diseases and gives a possibility to compare these ancient sequences with those of modern populations.