Greek Salad Dressing?

Okay, let’s get to some news.

From Discovery News, a report that scholars have been able to extract DNA from transport amphorae recovered from a shipwreck off the Greek island of Chios dating to the 4th century B.C. One contained olive oil blended with oregano (which the headline inexplicable calls ‘salad dressing’ – the text of the article, which says it would be used to ‘dress and flavor meals’ – is suitably vague given that it could have been used for lots of things. A second container contained DNA from the genus Pistacia, which could signal shipping of pistachio nuts but since amphoras are traditionally associated with transport of liquids, more likely signals wine blended with mastic, something akin to modern Greek resinated, or retsina wine. That would be particularly appropriate given the wreck’s location, as Chios in the Middle Ages was the primary supplier of mastic to Europe. That would also enable us to identify the wreck as a vessel leaving Chios, and not arriving there, which is consistent with some of the amphora types in the cargo, which are Chian. The source of the amphora containing the Pistacia DNA is not known, but if they contained Chian mastic, then logically they were probably made on the island as well.

The really cool thing is that the technique used to extract the DNA was extremely simple and could be applied to almost any pottery sample (though analyzing the DNA was no doubt time-consuming and expensive), meaning that we may have taken a major leap forward in our ability to source vessel contents. Oddly enough, given how crucial pottery is to reconstructing trade routes, our surmises as to what a vessel contained are often based on the flimsiest of evidence. In addition, there is a tendency to assume that if a particular amphora carried, say, wine, that every amphora of that type found was used to carry wine. We have enough evidence from multiple analyses to determine that transport vessels were rarely so strictly functionally segregated, but I think that as more such investigations are made there will be many more surprises in store.

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Ancient Greek Science

Tangled Bank is a weekly collection of blog stories and links on the topic of the biological sciences hosted in rotation by a series of science blogs. Something not usually relevant to the topic of this blog, except that this week's version, Tangled Bank #84, hosted by the Voltage Gate, uses Greek science as a unifying theme. Take a look!

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Interpreting DNA Evidence

Last week, I posted a link to a NYT article that discussed recent DNA studies of people and cattle in Italy. These studies found genetic similarities between current populations of both species in Italy and those in various regions of the Near East. This link was then interpreted as evidence that the ancient people known as the Etruscans arrived in Italy from the Near East (either directly or indirectly) sometime in the last three or four thousand years.

John Hawkes' has a post on his anthropology blog that examines another such attempt to use DNA evidence to reconstruct ancient migrations, this one published in Science. The results have been controversial, which has led to much scholarly back-and-forth. I thought this would be a salutary example of the dangers of overinterpreting DNA evidence. So what's the controversy?

For those wanting more detail, Hawkes ably sums up the issues involved, but in brief the evidence is this: DNA testing of people from North Africa found that they possess specific variations in their mitochondrial DNA similar to people living in the Near East. Based on the differences between these lineages and other mitochondrial DNA, we can estimate the time at which these groups branched off from their neighbors. In this case, the answer is about 45,000 years ago. The authors argue that this indicates that there was a migration into North Africa from the Levant around that time, displacing the earlier people that lived there. The date corresponds to the first peopling of Europe, and the authors suggest that both movements were part of the same pattern of migration.

Not so fast, say two other scholars. There are other ways for genes to move around. A later movement of peoples might have brought over these lineages. Or there might have been gradual diffusion of genes (via a series of short-distance interactions) instead of large-scale population movements. The archaeological evidence suggests that there was no large scale migration from Europe or the Near East into North Africa until much more recently, around 5000 BC.

For now, the evidence is insufficient to decide between the alternatives: 40,000 year-old mass migration? Slow diffusion? Recent mass migration? These are precisely the same problems that come into play in the Italian studies. Just because you share a common ancestry with someone 5000 years ago in the Near East doesn't mean that a bunch of people came over from the Near East at precisely that moment. There are lots of ways that genetic material can circulate.

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Bad Archaeology Reporting

Yesterday, the New York Times had an article about DNA evidence for the origin of the Etruscans that really raised my hackles at the bad reporting contained therein. To understand what all the hullabaloo is about, first we have to say a few words about who the Etruscans were and why we care about their origins.

The Etruscans were a people that lived in central Italy, just north of Rome, centered on an area that still bears their name, Tuscany. Their heyday ran from c. 600-300 BC, when they were absorbed into the growing Roman Republic. The Etruscans had a great influence on Roman culture; not only were two of the seven legendary Roman kings Etruscan, but more concretely, Etruscan art had a great influence on early Roman art. Perhaps most significant to us is the fact that the Etruscans gave the Romans their alphabet, which in turn is the ancestor of the one I am using to write this post.

The Etruscans are unusual in that the language they spoke is not related to any of the others spoken in Italy at the time. In fact, Etruscan is related to no known language. Etruscan is also not fully deciphered, although we can get the basic gist of most texts and certain Roman authors occasionally mention Etruscan words and their Latin equivalents. Sadly, the encyclopedic history of the Etruscans (who called themselves the Rasna) written by the Emperor Claudius doesn't survive.

The Etruscan language has led to all sorts of speculation about their origins. The Greek historian Herodotus tells us that the Etruscans (who he calls Tyrrhenians) originally came from western Asia Minor. He relates a story that during the reign of Atys, king of the Lydians (a legendary figure with no firm dates), the Lydians experienced a severe famine. To take their minds off their hunger, the Lydians invented board games -- a clear origin myth. When the famine continued, they decided to send half the population away under the leadership of the king's son, Tyrrhenius. They settled in Italy and became the Etruscans.

Herodotus' story was given great credence for many decades, until archaeological examination of both the Etruscans and Lydians showed that there is no identifiable connection between the two peoples. The Lydians spoke an Indo-European language quite unlike Etruscan, and there are no connections in pottery shapes or artistic iconography that would lead us to suspect any relationship. The closest archaeologists have been able to come are some short inscriptions found on the island of Lemnos -- off the coast of Turkey -- written in a language resembling Etruscan. The longest of these -- the so-called "Lemnos stele" -- dates to the 5th century B.C. Herodotus tells us the inhabitants of Lemnos were Pelasgians, the name given to the legendary pre-Greek inhabitants of the Aegean area. Thucydides says they were Tyrrhenians, or Etruscans. There does appear to be a linguistic connection, although since neither Etruscan nor Lemnian is fully deciphered, and since we have little Etruscan and less Lemnian preserved, we cannot reconstruct the exact relationship. The archaeological evidence does not support the idea of a recent migration in either direction, however.

Furthermore, the archaeological evidence from Italy shows a slow, steady development from the proto-Villanovan culture of c. 1100 BC to the Etruscans 500 years later. As a result, a consensus has grown that Etruscan culture and civilization was native to Italy and grew out of an Italian milieu, with no influx of outside peoples.

That brings us to the NYT article. It relates a series of DNA tests that have been performed on residents of the Italian city of Murlo, which rests on top of an Etruscan town, on contemporary residents of Tuscany, and on cattle breeds peculiar to the region. According to researchers, all of these populations bear certain genetic patterns that are close to people and cattle from the Near East. Dating DNA relationships is notoriously hard, and only the cattle study is reported as giving a date range: 6400 - 1600 BC. How's that for an error range!

There are two bad things about the NYT article, one egregious, the other less so but still worth pointing out. The first problem is the claim made in the title that this evidence "boosts Herodotus' account." This is nonsense. All of the relationships mentioned link the populations of central Italy to the Levant and Near East -- none to Turkey. Saying this evidence provides any support to Herodotus would be like archaeologists of the future discovering Viking settlements in North America and concluding they support the story of Columbus discovering the New World in 1492. Sorry, Herodotus is wrong. If the Etruscans did arrive from the Near East, it was in the distant past, long before any records Herodotus had access to.

The second bad thing is the continuing desire to use DNA analysis of modern populations to deduce ancient origins. More than two thousand years separate the people of Italy from their putative Etruscan ancestors, and much more than that from any possible migration. This study is better than most in that several independent chains of evidence are combined, instead of relying on a single sample. However, a lot of time has intervened, and there are other ways genetic material can travel other than via mass migration. For example, we know the Phoenicians had trading colonies in Etruria. In addition, in the late Bronze Age there was a series of catastrophes that resulted in the destruction of many civilizations in the Eastern Mediterranean, particularly the Mycenaean civilization in Greece and the Hittite kingdom in Asia Minor. Little is known about what happened, but at the same time Egyptian records report an invasion of outsiders the Egyptians called "Sea Peoples." Who the Sea Peoples were, why they attacked, and what connection, if any, they have with the collapse of Mycenaean and Hittite power are hotly-debated topics. For our purposes, some of the tribes the Egyptians list as making up the Sea Peoples have been linked with peoples of the Western Mediterranean: the Sheklesh might be the Sicels from Sicily, the Sherden from Sardinia, and the Tursa the Tyrrhenians (or Etruscans). Did the Etruscans participate in attacks on the Near East in the late Bronze Age? Did they perhaps take booty back with them?

This is speculation, nothing more, but is indicative of the way people and animals could move around in the ancient world.

Of course, the genetic link may be even farther back. Perhaps the Etruscans migrated into Italy at the start of the Neolithic period. We just don't know. Until we can find a more precisely-datable link, the origin of the Etruscans will still be a bone of contention.

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