The past hidden in our genes. Combining archaeological and genetic methodology: Prehistoric population bottlenecks in Finland
Year: 2014
Type: dissertation
Abstract: This doctoral dissertation combines archaeological and genetic methodology to find evidence of prehistoric population bottleneck(s) in Finland. This was performed by applying forward-time population genetic simulations with archaeologically justified development of population size. We ran different simulation scenarios to evaluate genetic effects of past demographic events and the results were compared with the known population genetic features of the current gene pool. In this thesis the focus in the simulations was on uniparental markers, the mitochondrion and the Y chromosome. The simulations were carried out in the forward time population genetic simulation environment simuPOP. The prehistoric Finnish population has not been previously simulated to this extent with population genetic simulations. In addition to genetic simulations, we performed analyses of the Stone and Ceramic Artefact Database as well as the radiocarbon date database to find out temporal differences in the intensity of the archaeological signal. We found similar evidence for a marked increase in the archaeological signal 4000-3500 cal BC followed by a distinct weakening. Previously, the Stone Artefact Database has been used to study singular artefacts and a few artefact types exclusively. This is the first time the Database including thousands of objects belonging to several Mesolithic and Neolithic time periods has been data mined to a large extent. Furthermore, we carried out a Bayesian spatial analysis of radiocarbon datings and archaeological finds from Finland and ceded Karelia, to better understand the overall geographical distribution of human activity through time. The analyses were carried out within the framework of Bayesian spatial modelling, using the Besag-York-Mollie (BYM) model to build spatial distributions of various archaeological datasets in Finland. This model is based on image analysis and assumes similarity of neighbouring areas in geospatial applications. The methodology presented here is one of the first efforts of applying Bayesian spatial analysis with different types of archaeological data in Finland. The main results of the study are: Archaeological and genetic evidence, together with the Stone Artefact Analysis, indicate that there has been at least one Neolithic bottleneck in Finland. Moreover, we show that immigration from neighbouring populations, even if very limited but constant over prolonged time periods, can have drastic effects on a population s genetic composition. Furthermore, our simulations showed that a tight prehistoric bottleneck can still have an effect on genetic diversity, even after thousands of years. With this kind of approach, we can evaluate the evidence in a more detailed fashion compared to solely an archeological or genetic approach.
Source: Työväentutkimus Vuosikirja
Author: Tarja Sundell
Language: English
Subfield: Genetics
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W1599912000