Stable population structure in Europe since the Iron Age, despite high mobility.

Ancient DNA research in the past decade has revealed that European population structure changed dramatically in the prehistoric period (14,000-3000 years before present, YBP), reflecting the widespread introduction of Neolithic farmer and Bronze Age Steppe ancestries. However, little is known about how population structure changed from the historical period onward (3000 YBP - present). To address this, we collected whole genomes from 204 individuals from Europe and the Mediterranean, many of which are the first historical period genomes from their region (e.g. Armenia and France). We found that most regions show remarkable inter-individual heterogeneity. At least 7% of historical individuals carry ancestry uncommon in the region where they were sampled, some indicating cross-Mediterranean contacts. Despite this high level of mobility, overall population structure across western Eurasia is relatively stable through the historical period up to the present, mirroring geography. We show that, under standard population genetics models with local panmixia, the observed level of dispersal would lead to a collapse of population structure. Persistent population structure thus suggests a lower effective migration rate than indicated by the observed dispersal. We hypothesize that this phenomenon can be explained by extensive transient dispersal arising from drastically improved transportation networks and the Roman Empire's mobilization of people for trade, labor, and military. This work highlights the utility of ancient DNA in elucidating finer scale human population dynamics in recent history.

[Eating disorders (ED) and obsessive-compulsive disorders (OCD): common factors]. / Troubles de l'alimentation et trouble obsessionnel-compulsif: facteurs communs.

Several similarities exist in the phenomenology of obsessive-compulsive disorder (OCD) and eating disorders (ED : anorexia nervosa and bulimia). Both disorders include obsessive thoughts and compulsive or ritualized behaviours. Furthermore, these two disorders frequently present with similar comorbid disorders. In this article, the authors examine similarities between ED and OCD, and whether eating disorders can be conceptualized as a variant of obsessive-compulsive disorders. This raises the possibility that treatments proven effective for OCD could be successfully adapted for ED. The authors consequently further examine both treatments utilized for both disorders.