Kiwi Genes Hint at a Unique Evolution
The kiwi bird is a flightless wonder, incredibly iconic and recognizable to even the most ignorant of bird watchers. Now, more than century after it was academically studied for the first time, scientists have successfully sequenced the animal's entire genome, and what they have found brings a whole new level of understanding for why they evolved as uniquely as they did.
The kiwi, which is strictly native to New Zealand and thus is the region's national bird, has several characteristics that make it unique even among flightless bird varieties. For one, it sports a uniquely primitive beak that is long-but-blunt and complete with nostrils. TIt also has no trail to speak of, and only rudimentary wings utterly incapable of lift. These little tufts of downy feathers on thick raptor feet also happen to be nocturnal, boasting a low basal metabolic rate and the lowest body temperature among birds.
According to a study recently published in the journal Genome Biology, those last two characteristics are very key to understanding the kiwi genome, as it was revealed that many of the bird's genetic changes were to accommodate for hungry night life. (Scroll to read on...)
For one, the kiwi seems to be utterly color blind, boasting genetic mutations that effectively inactivated the genes that would have played a part in color vision. However, in place of this, the bird seems to have expanded its sense of smell, boasting an impressive number of oderant receptor genes.
"Already French botanist and zoologist Jean Baptiste de Lamarck, who lived in the 18th century, hypothesized that evolution works in accordance with a 'use it or lose it' principle. It is therefore very likely that the kiwi lost its colour vision since this was no longer needed for its new nocturnal lifestyle," Diana Le Duc, a researcher with the University of Leipzig and first author of the study, explained in a statement. "The kiwi's sense of smell - which was required for foraging in the dark of the night - became more acute and the repertoire of odorant receptors increased adapting to a wider diversity of smells."
Unfortunately, the researcher and her colleagues also determined that the remaining wild brown kiwis in New Zealand - an endangered population threatened by invasive species - have very little genetic diversity. This, the scientists warn, could make the species more vulnerable than already throught, as even one disease could be enough to wipe them off the face of the Earth.
To avoid this, the researchers are proposing that conservationists consider intensive breeding programs to keep these unique and fascinating birds away from a disappointing end.
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