The Arrival of Steppe and Iranian Related Ancestry in the Islands of the Western Mediterranean

Abstract

53 54 55 56 57 58 A series of studies have documented how Steppe pastoralist-related ancestry reached central 59 Europe by at least 2500 BCE, while Iranian farmer-related ancestry was present in Aegean 60Europe by at least 1900 BCE. However, the spread of these ancestries into the western 61 Mediterranean where they have contributed to many populations living today remains poorly 62 understood. We generated genome-wide ancient DNA from the Balearic Islands, Sicily, and 63 Sardinia, increasing the number of individuals with reported data from these islands from 3 to 64 52. We obtained data from the oldest skeleton excavated from the Balearic islands (dating to 65~2 400 BCE), and show that this individual had substantial Steppe pastoralist-derived ancestry; 66 however, later Balearic individuals had less Steppe heritage reflecting geographic 67 heterogeneity or immigration from groups with more European first farmer-related ancestry. In 68 Sicily, Steppe pastoralist ancestry arrived by~2200 BCE and likely came at least in part from 69 Spain as it was associated with Iberian-specific Y chromosomes. In Sicily, Iranian-related 70 ancestry also arrived by the Middle Bronze Age, thus revealing that this ancestry type, which 71 was ubiquitous in the Aegean by this time, also spread further west prior to the classical period 72 of Greek expansion. In Sardinia, we find no evidence of either eastern ancestry type in the 73 Nuragic Bronze Age, but show that Iranian-related ancestry arrived by at least~300 BCE and 74 Steppe ancestry arrived by~300 CE, joined at that time or later by North African ancestry. 75 These results falsify the view that the people of Sardinia are isolated descendants of Europe's 76 first farmers. Instead, our results show that the island's admixture history since the Bronze Age 77 is as complex as that in many other parts of Europe. 78 79 86 Beaker complex had little if any Steppe pastoralist-related ancestry (from here on denoted "Steppe 87 ancestry"), but Beaker cultural practices were adopted by people in Central Europe were in part 88 descended from Steppe pastoralists and then spread this material culture along with Steppe 89 ancestry to northwestern Europe 4 . In Iberia, Steppe ancestry began to appear in outlier individuals 90 by~2500 BCE 4 , and became fully mixed into the Iberian population by 2000 BCE 5 . Meanwhile on 91 Crete in the eastern Mediterranean, there was little if any Steppe ancestry identified in all 92 published samples from the Middle to Late Bronze Age "Minoan" culture (individuals dating to 2400-93 1700 BCE), although these individuals derived about 15% of their ancestry from groups related to 94early Iranian farmers (from here on referred to as "Iranian-related ancestry") 6 (Fig. 1). 95In the islands of the central and western Mediterranean, the Bronze Age transition has not been 96 investigated with ancient DNA, despite the fact that archaeological evidence reveals that many of 97 the same cultural changes that affected mainland Europe and the eastern Mediterranean also 98...

Ancient genomes reveal social and genetic structure of Late Neolithic Switzerland

“…Therefore, it cannot be excluded, that these females also originate from regions further south since also some regions e.g., Italy are not genetically described so far for this particular time span. However, individuals without any steppe-related ancestry can be found up until 2479-1945 BCE for example in Iberia or until 2900-1700 BCE in the Minoan population of Crete 21,36 and even later on Sardinia where steppe-related ancestry arrives around 300 CE 37 and where studies of present-day Sardinians found indications of continuity in mountainous regions since Neolithic times 38 .…”

Genetic history from the Middle Neolithic to present on the Mediterranean island of Sardinia

“…The data also link Sardinia from the Iron Age onwards to the broader Mediterranean in what seems to have been a period of new dynamic contact throughout much of the Mediterranean. A parallel study focusing on islands of the western Mediterranean provides generally consistent results and both studies make clear the need to add complexity to simple models of sustained isolation that have dominated the genetic literature on Sardinia 52 . Finally, our results suggest some of the current substructure seen on the island (e.g., Ogliastra) has emerged due to recent genetic drift.…”

Ancient Rome: A genetic crossroads of Europe and the Mediterranean

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