DNA Study Traces the First Cultivated Olive to the North Levant
A large DNA study of wild and cultivated olive trees points to the northern Levant, near today’s border between Syria and Turkey, as the place where the olive was first domesticated. The paper, in the Royal Society’s biology journal, also finds three ancient refuges where wild olives survived the ice ages. Here is what the researchers did, what they concluded, and what it means for the olives we eat today.
What the study found
The team, led by Guillaume Besnard of France’s CNRS and including researchers from France, Spain, the UK, the US and Algeria, profiled the chloroplast DNA, which is passed down through the seed parent, of 1,263 wild olives, or oleasters, from 108 locations and 534 cultivated varieties. The paper was published online on February 6 in Proceedings of the Royal Society B and reported by Olive Oil Times this week.
| Finding | Detail |
|---|---|
| Trees sampled | 1,263 wild olives from 108 locations, 534 cultivated varieties |
| Wild refuges | Near East (including Cyprus), the Aegean, the Strait of Gibraltar |
| First domestication | Northern Levant, close to the Syrian and Turkish border |
| Highest wild diversity | Strait of Gibraltar |
| Nature of the process | Long, with repeated mixing between cultivated and wild trees |
The researchers found three main wild lineages, older than the ice ages, that survived in three long-term refuges: the Near East including Cyprus, the Aegean area, and the Strait of Gibraltar. Comparing the wild and cultivated patterns, they place the cradle of the first domestication in the northern Levant, with a mix of shared and unique genetic types found only in wild populations close to the Syrian and Turkish border. From there, they write, cultivated olives spread across the Mediterranean “in parallel with the expansion of civilizations and human exchanges.”
A puzzle, and an answer
If the richest wild diversity is at Gibraltar, why did domestication start in the east? The authors’ answer is people. Advanced early farming societies arose in the northern Levant, and they had enough genetic material to succeed with a tree that usually needs a second variety nearby to pollinate it. They describe domestication as a long and continuous process with many exchanges between cultivated trees and local wild ones, which may explain why earlier studies found signs of several origins.
The paper’s background notes the long-standing view that people started propagating the best olive trees in the Near East about 6,000 years ago, while wild olives were used from the Neolithic onward, from the Near East to Spain. Archaeology keeps adding to that picture, from olive presses in Israel (one of the oldest and largest olive press was discovered in northern Israel) to the uses of oil in ancient Greece (The Olive in Ancient Greece: Sacred Tree, Liquid Gold).
Why it matters today
- The wild refuges, especially around Gibraltar, hold diversity that plant breeders may need for disease resistance and new climates.
- The study treats wild olives as a resource worth protecting, not just scrub around the groves.
- The olive fruit fly, the crop’s main pest, shows a similar three-way split around the Mediterranean, the authors note, a hint that tree and pest share a long history.
Every olive region likes to claim its trees are the original. This study cannot tell you where your favorite variety was born, because it follows only the seed parent’s line and most varieties have been crossed with local wild trees for thousands of years. What it does show is that “ancient native variety” usually means a long mix of imported and local stock, which is exactly how most of the good ones came to be.