If you want to see an evolutionary dead end, look no further than the supermarket produce aisle. Every banana you eat is an infertile clone, and its wild ancestors weren't much better when it came to finding new genes.
This isn't good news for the bananas or one of their primary consumers (that'd be us). Because bananas are quite literally all exactly the same, any disease that hits one banana is pretty much certain to wreak havoc on an entire population. And since the vast majority of bananas are grown for local consumption, any disruption could create a famine in the surrounding area. In fact, the current most popular banana variety, the Cavendish, could become unsuitable for cultivation in the next 10 to 20 years. But a new study tracing the intertwined history of humans and bananas might offer some help.
That's the hope of researchers at the Australian National University, who used a mix of genetic, linguistic, and archaeological data to figure out not just how bananas spread across the world, but also what role humans played in that process. Research leader Mark Donohue explains:
"The genetic descent is one thing, but knowing whether they are being used by humans is another. The archaeologists could tell us when they were actually being used, the geneticists could tell us which direction and which kind of cross-breeding happened and, through the linguistics, we managed to get an idea of how culturally important bananas were for the regions they were in."
We know that bananas originated in Southeast Asia, and the archaeological evidence points to their first domestication taking place in what's now Papua New Guinea about 7,000 years ago. Genetic analysis can then pick the story up and tell us that bananas then began hybridizing on the surrounding islands and landmasses in ways that must have required human cultivation. The researchers also found over 1,100 terms for bananas in various languages, and they've been able to trace four key dispersal patterns based on the different words.
This research gives us some insight into how bananas became so inbred and, perhaps, how we can work to reverse that trend. Donohue argues that any solution will require the creation of local diversity for bananas so that one banana can no longer take down an entire population. That said, the real hope for the researchers - and banana cultivators - is to find the one banana type out of the hundreds of still undiscovered wild varieties that can be resistant to disease.
"Many parts of the world, like Indonesia, don't really know the sort of genetic diversity that's out there - there's never been a survey. Given the different kinds of climate we see, from New Guinea to South East Asia, there's probably a specialized variety, already being grown or present in the wild, that can hit that [disease resilient] niche quite well if we could only find it."
Via Discovery News.
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