How are you different from your ancestors

The analysis of ancient DNA shows that the ancestors of the biblical Philistines came from Europe

Research Report 2019 - Max Planck Institute for the History of Man

Feldman, Michal; Krause, Johannes
Department of Archaeogenetics
In the laboratories of the Department of Archaeogenetics, we examined the genetic makeup of people who lived in the Philistine city of Ashkelon around 3,600–2,800 years ago, that is, at the transition from the Bronze to the Iron Ages. The analysis showed that a European gene component reached Ashkelon in the early Iron Age. This indicates that the ancestors of the Philistines migrated from southern Europe across the Mediterranean and that the marked cultural change at that time in Ashkelon and other cities in the region was accompanied by the immigration of people.

In the 12th century BC, at the transition between the Bronze and Iron Ages, the cities of Ashkelon, Ashdod and Ekron experienced a substantial cultural change on or near the coast of today's Israel. As a result, they differed in their architectural traditions and their material culture from neighboring settlements [1].

The Old Testament counts these three cities among the five core cities of the "Philistines", the arch enemies of the Israelites. Scientists have long discussed whether the appearance of the so-called “Philistine phenomenon” was also linked to the migration of a new population group, and if so, where these people came from. To help clarify this question, we first examined the genome of people who lived in Ashkelon during this period in the laboratories of the Department of Archaeogenetics [2].

Only ten percent of the samples contained enough DNA for analysis

In total, we sampled skeletal parts from 108 individuals whose remains were excavated between 1997 and 2016 by the "Leon Levy Expedition to Ashkelon" in the area of ​​the Philistine city of Ashkelon. For the samples, we mainly took bone powder from the petrous bone - a part of the inner ear that conserves DNA particularly well. Genetic material that had been preserved from this powder was extracted by means of DNA extraction and then reproduced. Ten of the samples contained enough DNA to reconstruct the genetic make-up of these individuals genome-wide and to compare their genetic composition with that of other individuals from the past and also today [3, 4].

It was not surprising that only around ten percent of the samples we took were suitable for analysis. Earlier studies had shown that the climatic conditions in the region are extremely unfavorable for the conservation of DNA. The ten reconstructed genomes were dated to an age between 3,600 and 2,800 years, that is, they also cover the transition period from the Bronze to the Iron Age.

Genetic discontinuity between Bronze and Iron Ages in Ashkelon

The comparison of the ten genomes newly reconstructed by us with previously published data sets from earlier and present population groups showed that most of the genome came from the local Levantine gene pool over the entire period. However, people who lived in Ashkelon in the Early Iron Age had a European ancestry component that was not yet present in the Bronze Age inhabitants of the region [5].

This genetic difference is due to a gene flow that reached Ashkelon from the west across the Mediterranean at the end of the Bronze Age or the beginning of the Iron Age. This is consistent with estimates based on archaeological and written records of the arrival of the Philistines on the south-east coast of the Mediterranean.

Our modeling suggests a southern European gene pool to be the most plausible source. Further sampling and analysis could help identify the population through which the European component reached Ashkelon.

The influence of the European component was short-lived

When analyzing the DNA of people who lived in Ashkelon in the later Iron Age, the European component could no longer be detected. In other words, within no more than two centuries, the genetic footprint that was introduced in the early Iron Age seems to have merged into the local gene pool. This suggests an intensive mix between traditional and newly immigrated population groups.

According to the ancient texts, the people of Ashkelon remained “Philistines” for their neighbors in the 1st millennium BC. A differentiation based on their genetic makeup was no longer given at that time.

Archaeogenetics helps answer historical questions

Our study is another example of how archaeogenetics can help answer long-standing questions about human history. For the region of the eastern Mediterranean coast (Levant), the genetic data of our study are beginning to fill a time gap by showing that the local gene pool lasted for more than a millennium over the entire Bronze Age.

At the same time, we were able to show that the unique cultural characteristics of the early Philistines are reflected in a temporary specific genetic signature. This knowledge and the short-lived nature of the European gene component underlines the importance of samples that are closely spaced in time for the investigation of historical questions. Temporary genetic influences might otherwise be overlooked, which could lead to incorrect conclusions.

Bibliography

The Philistines and Aegean Migration at the End of the Late Bronze Age
Cambridge University Press, Cambridge (2014)
Feldman, M .; Master, D. M .; Bianco, R. A .; Burri, M .; Stockhammer, P. W .; Mittnik, A .; Aja, A. J .; Jeong, Ch .; Krause, J.
Ancient DNA sheds light on the genetic origins of early Iron Age Philistines
Science Advances 5/7, eaax0061 (2019)
Master, D. M .; Stager, L. E .; Yasur-Landau, A.
Chronological observations at the dawn of the Iron Age in Ashkelon
Egypt and the Levant / Egypt and the Levant 21, 261–280 (2011)
Mathieson, I .; Lazaridis, I .; Rohland, N .; Mallick, S .; Patterson, N .; Roodenberg, S. A .; Harney, E .; Stewardson, K .; Fernandes, D .; Novak, M .; Sirak, K .; Gamba, C .; Jones, E. R .; Llamas, B .; Dryomov, S .; Pickrell, J .; Arsuaga, J. L .; de Castro, J.M.B .; Carbonell, E .; Gerritsen, F .; Khokhlov, A .; Kuznetsov, P .; Lozano, M .; Meller, H .; Mochalov, O .; Moiseyev, V .; Guerra, M.A. R .; Roodenberg, J .; Vergès, J. M .; Krause, J .; Cooper, A .; Alt, K. W .; Brown, D .; Anthony, D .; Lalueza-Fox, C .; Haak, W .; Pinhasi, R .; Reich, D.
Genome-wide patterns of selection in 230 ancient Eurasians
Nature 528, 499-503 (2015)
Harney, E .; May, H .; Shalem, D .; Rohland, N .; Mallick, S .; Lazaridis, I .; Sarig, R .; Stewardson, K .; Nordenfelt, S .; Patterson, N .; Hershkovitz, I .; Reich, D.
Ancient DNA from Chalcolithic Israel reveals the role of population mixture in cultural transformation
Nature Communications 9, 3336 (2018)