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Kiwi may be
Australian export
Research published in Nature this week says the brown, flightless bird is more closely related to the Australian cassowary and emu than to New Zealand’s extinct moa. Alan Cooper and researchers at the University of Oxford made the discovery while sequencing DNA from the moa, a large flightless bird which went extinct in New Zealand 400 years ago and also once lived in Madagascar. The British research represents the first time a complete DNA sequence has been obtained from any extinct species. However, the sequence is only from the mitochondria, not from the nucleaus. Mitochondria are tiny organelles within the cell which generate energy. Geneticists believe this type of DNA mutates at a steady rate, making it possible to work out how long ago different species diverged. The team used genetic material extracted from the leg bones of two 1400 year old New Zealand moas (skeleton pictured below), and also analysed DNA from an extinct Madagascan elephant bird. This DNA was compared with living flightless birds: the kiwi, cassowary, emu and the African ostrich and South American rhea. Signficantly, the evolution patterns of this bird group match the breaking up of Gondwanaland, the ancient supercontinent which became Africa, Madagascar, South America, India Australia and New Zealand. The South American rhea was the first to split from the ratite ancestor, common to all the flightless birds, about 89 million years ago. This was about the same time South America and Africa split apart. Then the moas diverged about 82 million years ago, coinciding with previous estimates of the period when New Zealand split away. This was followed by the ostrich diverging about 75 million years ago. The kiwi diverged about 68 million years ago, after New Zealand is estimated to have split. Researchers therefore suggest it may have made it to New Zealand later, via land links through New Caledonia. The successful sequencing has again raised the idea of cloning extinct animals. However, Dr Cooper said the experiments had brought home to him the incredible difficulties of sequencing long stretches of ancient genetic material. "Most of genomic DNA is 'junk DNA' - highly repetitive sequences which are almost impossible to link up correctly, particularly from tiny fragments of deteriorated DNA," he said. "Jurassic Park is a nice idea, but ultimately it seems that it will be impossible for us to clone extinct species, and therefore it is critical that we do not become complacent in our conservation efforts and start assuming that we will be able to bring things back to life if they do become extinct." More
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