I've Got a Lovely Bunch of Coconut (Genetics)

If the venerable gentlemen of Monty Python have taught me anything, it’s that there is a lot you can do with coconuts. While making horse-clomping sounds and ad-hock bikinis spring to mind, researchers are using these psuedo-nuts for a more academic pursuit: studying early human movements in the southern seas. More than just delicious tropical beverage containers, coconuts can tell us a lot about travel and colonialism thousands of years ago. From DNA to ancient trade routes, scientists are shining a light on ancient history with modern biology.

photo credit: www.hotbeautyhealth.com

We might worry about long weekend traffic when setting out for a summer getaway, but we rarely stay home for fear of inadequate food and drinking water. A concept that is often overlooked in our grocery store culture is how much the availability of food has shaped our societies. Case in point: human exploration and societal expansion in the tropics was directly influenced by the coconut. Not only did this fruit-bearing palm provide a convenient source for a key piña colada ingredient, it also represented a portable source of water, oil, fuel, and building materials. By virtue of these life-sustaining qualities, this single plant played an enormous role in the ability of would-be navigators in the southern Pacific and Indian oceans to exercise their sea legs thousands of years ago.

            As Sir Isaac Newton so eloquently phrased his own musings on coconuts: “every action has an equal and opposite reaction.” While coconuts were enabling early globetrotters to set sail, these same expeditions were helping to spread the coconut plant throughout the tropics. Furthermore, people were cultivating coconuts to have specific human-friendly traits. Shorter, self-pollinating plants bearing rounder, juicier fruit allowed people to spend less time climbing and growing palm trees, and more time chowing down on sweet coconuts. From this point of view, our societies are built on what we eat, but we also have a formative influence on our dinner. Ah the tangled food webs we weave.

            Now that we know just how tied up our early exploratory urges were with coconuts, how can these fibrous historians give us insight on human history? The answer lies, like so many things in this genomic age, in their DNA. Researchers compared genetic markers from 1322 coconuts from all over the world and used this information to trace the development of modern coconuts from various geographic locations. They found that coconut cultivation was started independently in two locations: the outskirts of the southern Indian coast, and the south Asian seas between the Malay Peninsula and New Guinea. What's more, they could trace ancient nautical trade routes connecting Madagascar and southeast Asia by observing where the genetic signatures of the two lineages mixed. Coconuts growing on these ancient trade routes still have blended genetics, while those growing in environmentally similar conditions but off the main drag clearly belong to one group or the other. This data, and associated historical records, also shows the Philippine origin of Panama coconuts planted 2250 years ago, that the Spanish brought coconuts from the Pacific to Mexico, and how Caribbean coconuts brought by Europeans were originally picked up in India.

The ever-present human urge to modify and exploit our surroundings usually results in a fascinating tangle of anthropology and biology. No man (or society) is an island, but without each other, both us and the coconuts might have been stuck there.