In part (III) three possible genetic nomenclatures are being discussed. The study of ancient human DNA was regarded as likely not feasible, due to the fact that modern human contamination was shown to be abundant in ancient remains and could not be distinguished from the DNA of our ancestors.
The advent of next generation sequencing technologies and the establishment of reliable criteria to authenticate ancient DNA, such as DNA damage patterns, however, have made it possible in the last five years to generate and analyse authentic genome-wide ancient DNA data from a large number of individuals.
Genome-wide ancient DNA analysis of skeletons retrieved from archaeological excavations has provided a powerful new tool for the investigation of past populations and migrations.
An important objective for the coming years is to properly integrate ancient genomics into archaeological research.
The first genome-wide ancient DNA studies reporting these findings grouped samples mainly using geographical terms in combination with relative time periods and/or subsistence practices, like Mesolithic Europeans or Scandinavian hunter-gatherers (see Table 1, 1–3)The amount of genome-wide data has continued to increase massively, leading to the identification of more and more genetic groups and sub-groups.
Since 2015, nearly all DNA papers on Western Eurasia have used what we would like to call “mixed systems” for the naming of genetic clusters. subsistence practices (like “hunter-gatherer”), and 4. names of archaeological cultures (like “Yamnaya”) (For more detail on naming conventions and names, see Table 1). In Table 1 we call this nomenclature “mixed system (a)”.The term Western European hunter-gatherer, originally introduced by Lazaridis et al..In other cases the authors decided to use names of archaeological cultures that are usually also, but not always, combined with the relative dating.All of these systems are based on the same four elements for inventing names that they variably combine and order: 1. The “mixed system (a)” usually combines two of the four elements mentioned.For example individuals from present-day Spain dating to the Early Neolithic are called Spain_EN, individuals from the site Esperstedt in Germany, dating to the Middle Neolithic are designated Esperstedt_MN.These can be summarised in five words: brevity, coherence, accessibility, flexibility, and stability.Brevity: Each name used in the papers should be as short as possible while containing sufficient detail to distinguish the cluster from other genetic clusters in the same study and beyond.This led to names like Bell_Beaker_LN (Bell Beaker Late Neolithic), Starcevo_EN (Starčevo Early Neolithic), and Yamnaya.Nevertheless, the selection of terms is neither unreflective nor arbitrary, since the ‘mixed system (a)’ incorporates some features which are of considerable importance for the applicability of nomenclatures in general.For example individuals associated with the Bell Beaker Complex are not genetically homogeneous across Europe, and thus it is in genetic terms appropriate to use classifications that distinguish subgroups, e.g. Flexibility: The nomenclature needs to be flexible enough to adjust when there are new genetic findings.An appropriately flexible nomenclature should offer the possibility of both subdividing previously named groups into smaller ones and merging clusters which were at first found to be distinguishable.