You may have heard of this by now:
B. F. Gunn et al, Independent Origins of Cultivated Coconut (Cocos nucifera L.) in the Old World Tropics. PLoS ONE 2011. Open access.
I was a bit perplex at first because what I have read around is that this paper somehow demonstrates that coconuts only spread with human domestication and colonizing flows. This is a most extreme claim which hardly fits the nature of this plant, which is not truly a domesticate but a widely exploited wild plant in fact. It is a very hardy plant that grows primarily at the high tide line and is naturally transported across the oceans by mere drift.
|Fig. 2 has the essence of the paper|
It is evident from this paper that coconuts have at least two distinct ancestral populations: one seemingly originated in South Asia and the other from SE Asia/Pacific, that its dispersal to the Atlantic Ocean happened necessarily with human help and that the East African population while essentially the Indian variety, has some admixture from the SE Asian/Pacific variants.
This last element is argued by the authors to signify human influence by means of the Austronesian colonists of Madagascar. While this is plausible I see no definitive argument for this logic in fact. Similarly I fail to see the hand of Austronesians in the Pacific scatter as something cast on iron, rather as just a possibility.
The only clear case of human intervention are the Dwarf variants because they are self-pollinating and this is not a trait you typically find in wild plants. But the Dwarf component is relatively rare and is not even present in the alleged Austronesian-mediated arrivals to East Africa and South America (Panama variant).
So I am not really persuaded of their thesis that most of this structure was caused by humans. It is possible but very far from demonstrated in fact.
Regardless, what eventually brought me to write this entry was after all their other discovery, which is quite solid and obvious: that in spite of the palm being so widely exploited and moved around in the Modern Era, the original genetic structure has persisted almost unaffected.
This is quite astonishing because copra (dried coconut flesh) and palm oil, as well as the fibre and the fresh fruit, so suitable as natural preserve for the long travels of sailors of not so long ago, make the coconut a clear candidate for extensive alteration of its ancestral genetic landscape, yet it has resisted all that almost impassible in all its range from Africa to South America.
A lesson to be assimilated by all those who happily proclaim that established populations can easily be altered. It can happen indeed but it is not easy.