Origins of olive tree revealed


Share post:

The olive was first domesticated in the Eastern Mediterranean between 8,000 and 6,000 years ago, according to new research.

The origins of the olive tree revealed
Olives, like the Salonika variety pictured here, were likely first domesticated in the Levant around 6,000 years ago, new research suggests [Credit: Jean Paul Roger]

The findings, published today (Feb. 5) in the journal Proceedings of the Royal Society B, are based on the genetic analysis of nearly 1,900 samples from around the Mediterranean Sea. The study reveals that domesticated olives, which are larger and juicier than wild varieties, were probably first cultivated from wild olive trees at the frontier between Turkey and Syria.

“We can say there were probably several steps, and it probably starts in the Levant,” or the area that today includes Israel, Palestine, Jordan, Lebanon and Syria, said study co-author Gillaume Besnard, an archaeobotanist at the National Center for Scientific Research in France. “People selected new cultivars everywhere, but that was a secondary diversification later.” 

From biblical times, the olive tree has served as a symbol of sacredness, peace and unity. Archaeologists have unearthed olive pits at sites dating to about 8,000 years old. And dating as far back as 6,000 years ago, archaeologists find evidence of olive oil production in Carmel, Israel, Besnard said.

Yet exactly where the olive was first cultivated has been hotly debated. 

To unravel the history of the olive tree, the team took 1,263 wild and 534 cultivated olive tree samples from throughout the Mediterranean and analyzed genetic material from the trees’ chloroplasts, the green plant structures where photosynthesis takes place. Because chloroplast DNA is passed from one tree to the descendant trees that spring up around it, the DNA can reveal local changes in plant lineages, he said.

The researchers then reconstructed a genetic tree to show how the plant dispersed. The team found that the thin, small and bitter wild fruit first gave way to oil-rich, larger olives on the border between Turkey and Syria.

After that first cultivation, modern-day domesticated olives came mostly from three hotspots: the Near East (including Cyprus), the Aegean Sea and the Strait of Gibraltar. They were then gradually spread throughout the Mediterranean with the rise of civilization.

But to get a true sense of how the olive tree emerged, the researchers shouldn’t just look at chloroplast DNA, said AndrĂ© BervillĂ©, a geneticist at the French National Institute for Agricultural Research, who was not involved in the study. Nuclear DNA, which is carried in the pollen, should also be analyzed, BervillĂ© told LiveScience.

“Pollen from the olive tree is wind-transported, so it can migrate long distances” he said.

Combining both types of DNA would allow researchers to understand both how local olive tree cultivation occurred and how more long-distance changes occurred, he said.

Author: Tia Ghose | Source: LiveScience [February 05, 2013]



Related articles

Pulsating star sheds light on exoplanet

A team of researchers has devised a way to measure the internal properties of stars -- a method...

Study finds ratio between speed of evolution, population change

Does evolution really trundle along like Darwin's famous Galapagos tortoise? And do the populations undergoing this evolution really...

Research identifies icy ridges on Pluto

Using a model similar to what meteorologists use to forecast weather on Earth and a computer simulation of...

‘Seeds’ of massive black holes found at the centre of the Milky Way

Many galaxies contain enormous amounts of molecular gas in small areas near their nuclei. Highly condensed molecular gas...

Telegraph: Greece has no legal claim to the Elgin Marbles

The Greek government has finally acknowledged that the British Museum is the lawful owner of the “Elgin Marbles”....

Leonardo da Vinci’s DNA: Experts unite to shine modern light on a Renaissance genius

A team of eminent specialists from a variety of academic disciplines has coalesced around a goal of creating...

Marine biodiversity loss due to global warming and predation, study predicts

The biodiversity loss caused by climate change will result from a combination of rising temperatures and predation --...

Climate will damage reefs at ‘different rates’

Climate change and acidifying ocean water are likely to have a highly variable impact on the world's coral...