Determination of different predictors affecting DNA concentration isolated from historical hairs of the Finnhorse

Everyday objects manufactured from raw materials of animal origin, such as skin, hair and bone, are innumerable in cultural historical museums and private collections. Besides their value as memoirs of past techniques, livelihoods and communities, they are a unique source for studying past animal populations by means of molecular analysis. Here, we deal with horse mane and tail hair, a type of predecessor of modern synthetic material utilized, for example, for brushes, strings, tennis rackets, ropes, textiles, dolls’ hair, rocking horses, and filling. By investigating the presence and quality of DNA in horsehair, we have studied the origins of the Finnhorse, the only native horse breed in Finland. Degradation of DNA in old samples is an issue that needs to be considered when selecting material for DNA analysis. For assessing the usability of historical artefacts for DNA-based studies, we study how DNA is preserved in horsehair and how well DNA can be isolated from 50 to 150-year-old artefacts, raw material bundles and archaeological finds. We investigate how the properties of hair and sample storage conditions affect the concentration of DNA extracts and success in Polymerase Chain Reaction (PCR). Our analysis showed that historical hair shafts, stored in various environments and used for multiple purposes, are of sufficient quantity and quality for amplification by PCR. Therefore, their value for the research of past animal populations should be noticed when curating cultural historical collections. We also provide advice for the storage conditions for hair samples.