By Jimmy Breen
Wheat is one of the major parts of human diet for most of the world’s population, despite the fact it (and other gluten-containing foods) tend to get a bum rap nowadays due to food-based gluten intolerance in western societies. Travel the world and, on most continents, there’s a good chance that you’ll encounter a big pile of bread (in some form) on the dinner table. Particularly in Westerner/European culture, bread is everywhere, from pastries and pies to flatbreads and baguettes. Beyond wheat, other grains also feature highly in our diets: oats and barley, for example. The wide-spread presence of grain-based foods in modern diets today is due, in part, to our human cultural evolution.
After the last glacial maximum (LGM), around 20,000 years ago, the earth began an extended warming period where conditions for plant growth began to improve. Around 12,000 years ago, hunter-gatherers that occupied the Fertile Crescent (a region encompassing most of the Middle East from Egypt to Iran; shown in the figure below), started to deliberately plant the wild species of plants that they usually foraged (e.g. lentils, wheat, barley, pea and chickpea). This planting of seeds would become more and more systematic, so beginning subsistence agriculture. At a similar time, in the same region, other populations of humans were herding and tending large groups of wild species of sheep, goats, and cattle. Over time, people began to select the most useful plant and animal breeds to continue breeding. This artificial selection of plant and animal species is called “domestication” and has shaped many of the species we now see today.
Regular crops and animals meant people started storing food, allowing larger communities to form, rather than the small groups that had existed previously. As people started living together, they interacted, which allowed the formation of cultural activities such as trade, writing, art, music, and religion. Imagine a world without hip-hop! (that’s no world I want to live in…)
As one of these founding crops, wheat has been continually bred to a point where it is unrecognisable from its wild relatives. Continual inbreeding has caused the loss of many significant genes, making it difficult to increase yields with conventional selective breeding that has been used by humans for centuries. One way of preventing this “bottleneck” is to introduce new genes into the domestic variety by crossing modern wheat varieties with wild relatives still growing in the Near East, or to breed with locally adapted wheats from different parts of the world (this is the basis of the “Green Revolution” in the 1970s, where Dr. Norman Borlaug won the 1970 Nobel Peace Prize).
What if we could go back in time and identify genetic diversity that we have lost during the breeding process? Could that give us insights into past genes, and save millions of people from starvation in the future?
Well, in July last year while some ACAD’ers were trudging through the Yukon collecting Bison bones and plants, or abseiling into North American caves, I was weaving my way through the Trans-Caucasian countries of Georgia and Armenia, visiting museums and archaeological sites in search of ancient wheat and barley material.
ACAD, in collaboration with the School of Agriculture, Food and Wine are sequencing the DNA of ancient cereals grains from these Near East regions to investigate the genes that existed in the past. With the help of researchers in Ireland, the UK, and Armenia, we are sequencing ancient cereal seeds and comparing them to modern cultivars.
One of the major sites on our ancient cereals project is the Areni-1 cave in Southern Armenia. Despite being located in a fairly contentious political region (map shown), Armenia contains some of the best-preserved Bronze Age and Chalcolithic sites in the near east. It also contains some very important wild wheat species and unique grape varieties. The area around Areni-1 cave is a town called Areni that grows its own wine variety (auspiciously named Areni) and grows other crops such as wheat and fruit orchards.
As I mentioned, this region of the world is one of the native areas of founding crop species. Just outside the cave I found one of the diploid ancestors of modern wheat called Aegilops tauschii, along with other grass species.
The cave is a truly amazing site, with a large over-hanging rock shelter at the front. The cave stretches some 50-60m into the mountain, with small rooms being found everywhere. The cave contains a strange and wonderful array of clay pots that have been buried under sediment and sealed in via a layer of animal dung. These pots contain everything from human limbs, mummified children, human faeces and plant material. Head archaeologist at the site Boris Gasparian has published work suggesting the site was an important ritual site.
The amount of material that Boris has collected is truly remarkable, and, when I visited him at the National Academy of Sciences of Armenia in Yerevan, he showed me artifacts that had an outstanding level of preservation. The cave is home to some amazing artefacts such as the world’s oldest shoe as well as the oldest winery.
Stay tuned for some interesting research!