  This study analyzes rates and ways of data sharing regarding mitochondrial, Y
chromosomal and autosomal polymorphisms in a total of 162 papers on human
ancient DNA published between 1988 and 2013. For the most part, data are
available in such a way as to make their scrutiny and reuse possible. The
estimated sharing rate is not far from totality (97.6% +/- 2.1%) and
substantially higher than observed in other fields of genetic research
(Evolutionary, Medical and Forensic Genetics). A questionnaire-based survey
suggests that the authors awareness of the importance of openness and
transparency for scientific progress is a fundamental factor for the
achievement of such a high sharing rate. Most data were made available through
body text, but the use of primary databases increased with the application of
complete mitochondrial and next generation sequencing methods. Our study
highlights three important aspects. First, we provide evidence that researchers
motivations are as necessary as stakeholders policies and norms to achieve very
high sharing rates. Second, careful analyses of the ways in which data are made
available are an important first step to maximize data findability,
accessibility, useability and preservation. Third and finally, the case of
human ancient DNA studies demonstrates how Open Science can foster scientific
advancements, showing that openness and transparency can help build rigorous
and reliable scientific practices even in the presence of complex experimental
challenges.
