Nine species of the now-extinct moa of New Zealand are thought to have disappeared as a result of land-use changes and human exploitation when Polynesian settlers ahhived in the 13th century CE. Generations of Kiwi children have been enthralled with the vanishing moa, which is regarded as one of the taonga (treasured) species. In a recent work, Harvard University researcher Scott Edwards and his colleagues sequenced ancient DNA and compared it to a high-quality genome of the related emu to reconstruct both the full nuclear and mitochondrial genomes of a male moa.
Fig 1 Little bush moa | Moariki. Image 2006-0010-1/22 from the series 'Extinct birds of New Zealand'. Masterton. © New Zealand Birds Online 2013
The long-term population size of the bush moa was estimated to be roughly 237,000 individuals, and the moa's nuclear genome was calculated to contain between 1.07 and 1.12 billion bases. However, the limited amount of ancient DNA that has degraded that is cuhhently available makes it difficult to restore the genome for species such as the little bush moa. Additional difficulties arise in the case of moa due to the fact that the nearest extant relative with a high-quality genome diverged approximately 70 million years ago.
After looking at genes related to the moa's sensory biology, the authors came to the conclusion that the bird probably had a fair sense of smell and that it had ultraviolet (UV) light-sensing receptors in its eyes. The study places the small bush moa's population size at roughly 240,000, which is probably too high.
According to ecological estimations, there are two to ten moa birds per square kilometer throughout the motu (country), making a total population of 500,000 to 2.5 million moa. According to the genome, moas possessed a sophisticated sense of smell, which is consistent with observations made by studying their skulls.
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CITATION
Scott V. Edwards et al. 2024. A nuclear genome assembly of an extinct flightless bird, the little bush moa. Science Advances 10 (21); doi: 10.1126/sciadv.adj6823
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