BiorchivX is an odd online-media. It is a website to which you can upload your unpublished manuscripts before you publish them. This places the manuscript somewhere between unpublished (it has yet not gone through the peer-review system) and published (people can still download it and read it). Sort of like a vampire, not living, but neither dead.
Some time ago as study was published by Jakobssons group in Uppsala, showing that while the farmer-migration from Anatolia was a sex-neutral process, the later Yamnaya-migration into Europe from the Steppe was sex-biased, containing a whole lot more males than females. The assumption was based on X-chromosomal calculations, and became hot news in the field when it was published.
For those that are interested in ancient DNA and what you can do with it, there is now a debate going on about those results on BiorchivX. They were challenged by Reichs group in Harvard, who were not able to reproduce them (http://biorxiv.org/content/early/2017/03/14/114124). Jakobssons group, in turn, argues that the problem most likely originates from using too small reference samples (http://biorxiv.org/content/early/2017/04/03/122218). This is an interesting debate about an interesting subject that I hope will eventually be properly published and possible to cite.