Looking at Sardinian DNA for genetic clues to an island’sand … – Phys.Org

February 13, 2017 DNA double helix. Credit: public domain

Sardinia sits at a crossroads in the Mediterranean Sea, the second largest island next to Sicily. Surrounded by sparkling turquoise waters, this Mediterranean jewel lies northwest of the toe of the Italian peninsula boot, about 350 kilometers due west of Rome.

For evolutionary biologists, islands are often intriguing, geographically isolated pockets with unique populations that can be ripe for exploration.

Now, in a new study appearing in the advanced online edition of Molecular Biology and Evolution an international team led by geneticist Anna Olivieri from the University of Pavia tackles a highly interesting question: what were the origins of the Sardinian population in the context of European prehistory and ancient human migrations?

The authors analyzed 3,491 modern, whole mitochondrial DNA genomes from Sardinia (which are only passed down maternally). These were compared with 21 samples of ancient mitogenomes from the island, a large panel of non-Sardinian mitogenomes -and even tzi (the nickname of Europe's oldest natural mummy, the 3,300 BCE-year old "Tyrolean Iceman") -to better understand their origins.

Their findings show Sardinia as an outlier in the general European genetic landscape. Almost 80 percent of modern Sardinian mitogenomes belong to branches that cannot be found anywhere else outside the island. Thus, they were defined as Sardinian-Specific Haplogroups (SSHs) that most likely arose in the island after its initial occupation. Almost all SSHs coalesce in the post-Nuragic, Nuragic and Neolithic-Copper Age periods. However, some rare SSHs display age estimates older than 7,800 years ago, the postulated archeologically-based starting time of the Neolithic in Sardinia.

"Our analyses raise the possibility that several SSHs may have already been present on the island prior to the Neolithic," said prof. Francesco Cucca, from the Institute of Genetic and Biomedical Research (IRGB), at the CNR in Cagliari (Sardinia).

The most plausible candidates would include haplogroups K1a2d and U5b1i1, which together comprise almost 3 percent of modern Sardinians, and possibly others. Such a scenario would not only support archaeological evidence of a Mesolithic occupation of Sardinia, but could also suggest a dual ancestral origin of its first inhabitants. K1a2d is of Late Paleolithic Near Eastern ancestry, whereas U5b1i1 harbours deep ancestral roots in Paleolithic Western Europe.

This work provides evidence that contemporary Sardinians harbour a unique genetic heritage, as a result of their distinct history and relative isolation from the demographic upheavals of continental Europe. Anna Olivieri stresses: "It now seems plausible that human mobility, inter-communication and gene flow around the Mediterranean from Late Glacial times onwards may well have left signatures that survive to this day. Some of these signals are still retained in modern Sardinians."

"Although in the past the stress has often been on the spread of the Neolithic, genetic studies too are beginning to emphasize the complexity and mosaic nature of human ancestry in the Mediterranean, and indeed in Europe more widely," concludes prof. Antonio Torroni, from the University of Pavia. "Future work on ancient DNA should be able to test directly to what extent this more complex model is supported by genetic evidence, and whether our predictions of Mesolithic ancestry in contemporary Sardinians can be sustained."

Explore further: Hair from mummy's clothes provides insights into red deer lineage

More information: Anna Olivieri, et al, Mitogenome Diversity in Sardinians: a Genetic Window onto an Island's Past, Molecular Biology and Evolution (2017). DOI: 10.1093/molbev/msx082

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An ancient people of Sardinia were once called the Shardana...... as in Shar-DAN-a. They were one of the 'Sea Peoples' that plyed the Mediterranean during the Greek Dark Ages, as were the Danoi or DAN-oi of Mycenea and the Dan-nan-oi or DAN-nan-oi of Thutmose's Egypt and the Israeli Tribe of Dan from Tel-Dor in Israel. All were of the 'Danites' and emanated from Israel about the time of the Exodus in the Torah, about 1500 BCE. There is physical archaeology indicating all of this. For further distant antecedants, one need look at pre-Exodus Hebrews working as slaves in Egypt's 'Valley of Terror'. Cave inscriptions there bear some of first uses of modern alphabet.

Pronunciations in southern Europe and the Levant seem all relative to varying forms of pronunciation of alphabetic or abjadic letters. Russia, as remote as it seems, got much of its culture from ancient Dacia which is where also later on the Kievan' Rus.......Ukraine, got started. The French suffix 'in' has its vowel sounding almost like a flat 'aanh'. These differing vowel pronunciations spread all across cultures from ancient Iberia to Capodoccia to Assyria to Ur across not only distance but also time measured in millennia. The Hebrew's ancient alphabet or 'alef-bet' came from Linear-A script copied into Heiratic in Egypt with its 600 letters whose' difficulty in learning was a purposeful act to prevent the common folk from educating themselves. That those secretive fuedal societies like the Hittites and Egyptian Pharoanics left so little behind seems a tribute to their shared interest in looting their present, uncaring of future progress.

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