Often crops have been domesticated so long ago it is difficult to trace their origins back to their wild counterparts. Not so in the case of the macadamia nut.
Researchers from Southern Cross University, and Queensland University investigated hundreds of DNA samples collected from macadamia trees in Hawaii. Using these samples, they were able to trace their ancestry back to a patch of wild growing macadamias in Queensland, Australia. They believe that seeds taken from these trees was taken to Hawaii in the 19th century, where they were planted in a garden. Once these trees flourished in this new environment, and people discovered the tasty macadamia nuts, they were then planted commercially.
The DNA evidence shows that 70% of the trees worldwide that grow this $3 billion crop are descendent from this one stand of native trees. As a result, they are all very genetically similar, which could pose problems. The researchers believe that genetic diversity could be reintroduced from wild populations, in order to improve future crops.
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