HOKKAIDO UNIVERSITY
Scientists have concluded that Hawaiian fruit flies do not have a single common ancestor, which had been the widely held theory. One of the fruit fly species included in the Japanese study was the Scaptomyza pallida, above.
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It wasn’t quite as easy as sending away for one of those home DNA kits, but Japanese scientists have determined that Hawaiian fruit flies, once believed to have come from a single common ancestor, are in fact the product of diverse and far-flung lineages.
The findings were published in the July 13 edition of the journal Entomological Science.
Hawaiian fruit flies are divided into Idiomyia, which are endemic to Hawaii, and Scaptomyza. About 60 percent of Scaptomyza species are unique to Hawaii; the rest are distributed around the world.
Scientists have previously held to the “single Hawaiian origin” theory that Hawaiian fruit flies (or drosophilids) came from a sole common ancestor that once colonized the Hawaiian Islands, and that the genus Scaptomyza later traveled to different continents.
However, a team of scientists from Hokkaido University and Ehime University determined the DNA sequence information for 11 kinds of non-Hawaiian Scaptomyza species and analyzed it against existing sequence information. They came to a significant new conclusion based on their results.
The scientists reconstructed the evolution and diversification of Hawaiian fruit flies and estimated ancestral distributions and divergence times, thereby inferring that they had multiple continental ancestors that independently migrated to Hawaii at different times.
The team, led by Toru Katoh, an assistant professor at Hokkaido University’s Division of Natural History Sciences, said it hopes for further study into non-Hawaiian fruit flies endemic to the Pacific islands.
On the Net:
phys.org/news/2016-08-hawaiian-fruit-flies-multiple-ancestors.html