I've decided, for the time being, to take a break from discussing and analyzing papers in human ancient DNA studies. The reason for this is that there seems to be little effort to properly establish a baseline for Paleolithic or Mesolithic ancient DNA patterns over geography; certainly not to the granularity where you could think about ecozone specialization, which was most certainly a factor in ancient population variation. The current proposed scenarios (for example "mass migration" of "red haired" invaders and Irish DNA originated in Middle East and eastern Europe) are juvenile at best. Many papers currently published repeat the same as yet unsupported scenario that the origin of Neolithic farmers is entirely from the "Middle East" during the Neolithic (with the "Middle East" seeming to vary anywhere between Thessaly and the Southern Levant), followed by Bronze Age "Steppe" warriors from "the Pontic steppe of southern Russia, who knew how to mine for copper and work with gold". It's all very biblical and neatly Bronze Age Steppe Hypothesis Indo-European Language Theory compatible. These papers are published in PNAS and Nature with evidently little effort to review them critically. Almost immediately afterward, like a machine, these papers receive heavy media attention over and above all other scientific publication.
Most of the authors publishing these ancient DNA papers all know each other and review each other's work. It is a small community of the same people. Through their use of social media, much of the research is discussed online under pseudonyms, with genomics professionals also posting their own work under pseudonyms. Moreover, these researchers make use of tweeters such as Debby Kennett (her area is geneology, not science) and Maria Arcos-Avila , and forum posts (for instance anthrogenica.com) by geneologists such as Jean Manco, to promote their work. Shockingly, both Debby Kennett and Maria Arcos-Avila often retweet posts from Razib Khan . . . yes, Razib Khan, pornography aficianodo and apparent race and cognitive psychology expert.
There is a consistent pattern in some of these papers, where skin, hair and eye color seem to be the primary focus. Given that the research is often funded under the rubric of medical research, it is highly mysterious as to why the funding in these ancient DNA papers have produced so few medically significant results, and have focused so much media attention on skin, hair and eye color.
For these reasons, my current focus is on archaeology, ecozone studies and cultural anthropology, and less on genetic anthropology.
Wishing you a Happy New Year.