New research uncovers why moas and kiwis lost ability to fly

Thursday, 4 April 2019

New research from the University of Otago supports the idea that moa and kiwi once flew to New Zealand.

Ever wondered how New Zealand's famous birds lost their ability to fly?

Looking further than the lack of big wings or no wings at all, researchers have tracked the endangered kiwi and extinct moa's loss of flight to their molecular roots.

The study - conducted by the University of Otago and Harvard University, and published in Science - analysed DNA from a number of flightless birds, or ratites.

The work provided researchers with greater insight into the origins of New Zealand's iconic birds - great and little spotted kiwi, Okarito kiwi and the extinct little bush moa.

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Dr Paul Gardner, a co-author of the study from Otago's Department of Biochemistry, believes this research supports the idea that moa and kiwi were once able to fly, prior to the extinction of dinosaurs.

'This work tells us more about the origins of moa and kiwi. It supports the hypothesis that the ancestral moa flew here, while the ancestral kiwi, which is related to the emu, may have walked, or indeed flown from the likes of Australia or Madagascar over the ancient Gondwanan continent,' he said.

Dr Michael Knapp from the Department of Anatomy at the University of Otago explained, 'within the group of ratites, the ability to fly has been lost at least three times independently'.

Researchers then looked at these specific genomes to see if the events 'are caused by similar processes'.

By comparing DNA sequences between the different birds, scientists found the regulatory DNA to be to blame for loss of flight, not the protein-coding DNA, which has been the focus of previous studies.

This suggests the lack of flight is affected by parts of the genome which can ultimately turn a gene on and off.

Gardner believes this collaboration and research provides scientists with a better idea 'that the places of genome that we concentrated on, the protein-coding genes, may not be in fact the ultimate source of species diversity and change'.

Scientists were able to identify 'most of the functional genes associated with wing development and flight' within the partial moa genome, according to Dr Nic Rawlence, the director of Otago Palaeogenetics Laboratory at the University of Otago.

Rawlence said this study's findings create an 'evolutionary mystery'.

This research helps scientists understand how the moa ended up with no wings at all. However, Rawlence explained greater samples would help them come to a concrete conclusion.

'More ratite genomes, especially additional moa and the extinct Madagascan elephant bird, would go a long way to finally resolving this debate.'

Other scientists in this field, including Massey University's Dr Gillian Gibb, praised the work of this study and the opportunities it presents for future studies.

'It is great that there are New Zealand scientists involved in this international research collaboration, and these published genomes will be a valuable future resource for all researchers.'