This demic diffusion model relies on the comparison of ancient and modern Y-DNA SNPs, by observing how patrilineal lineages are replaced in certain areas that belonged to certain archaeological cultures.
While analysis of whole genomes may be biased, whether by chance (drift) or by selection[Jobling et al. 2014], careful investigation of SNPs with help of anthropological disciplines can be used to obtain meaningful conclusions.
Examination of SNPs of the Y-chromosome of ancient individuals one by one seems more suited to the scarcity of aDNA samples available, and the quality of its recovery, since defects in the STR sequencing are frequent, and thus only certain SNP markers may be obtained, with less information – and higher subclades – obtained from the samples.
The date calculated for TMRCA of SNPs in modern populations has been used to define when certain migrations or expansions might have occurred. While it seems a good starting point for that purpose, it relies on the survival of modern populations related to such ancient population movements, and as such it could miss initially successful lineages that are now extinct, and that could have given an earlier date if they had been included in TMRCA calculations.
Ancient and modern mtDNA distribution analyses – although they can help more clearly determine migration paths[Brandt et al. 2013] and other interesting characteristics of ancient cultures, such as female exogamy[Sjogren, Price, and Kristiansen 2016] –, has not been included in this paper for simplicity purposes.
Potential language relationships have been used to illustrate the Indo-European demic diffusion model. Many long-term linguistic relationships beyond Middle Indo-European remain hypothetical at best – when not completely discarded with the current data –, and it is not the intention of this paper to support or dismiss such connections. Such relationships – like Indo-European dialectalisation – must be proven by linguistic research, and archaeology and genetics can only add precision to such studies.
While the theory here presented seems rational and scientifically sound, there are many alternative explanations that could have been made of the same data: these have been omitted for the sake of simplicity.
More ancient DNA samples are needed to precisely draw most details of the general theory laid out in this paper.
- [Brandt et al. 2013] ^ Brandt, G., W. Haak, C. J. Adler, C. Roth, A. Szecsenyi-Nagy, S. Karimnia, S. Moller-Rieker, H. Meller, R. Ganslmeier, S. Friederich, V. Dresely, N. Nicklisch, J. K. Pickrell, F. Sirocko, D. Reich, A. Cooper, K. W. Alt, and Consortium Genographic. 2013. Ancient DNA reveals key stages in the formation of central European mitochondrial genetic diversity. Science 342 (6155):257-61.
- [Jobling et al. 2014] ^ Jobling, M. A., E. Hollox, M. MHurles, T. Kivisild, and C. Tyler-Smith. 2014. Human Evolutionary Genetics. Second edition ed. New York and Abingdon: Garland Science, Taylor & Francis Group.
- [Sjogren, Price, and Kristiansen 2016] ^ Sjogren, K. G., T. D. Price, and K. Kristiansen. 2016. Diet and Mobility in the Corded Ware of Central Europe. PLoS One 11 (5):e0155083.