Genome sequencing key to kakapo survival

Genome sequencing has given hope to conservationists working with critically endangered kakapo.

The new research could even lay the groundwork for a breeding strategy for the flightless parrots that once only had 51 individuals left, University of Otago department of zoology Prof Bruce Robertson said.

The research showed small populations of the birds could survive even if isolated for hundreds of generations, Prof Robertson said.

Unlike today, when the species is on the brink of extinction, kakapo once lived in huge numbers in the South Island; nearly 500,000 lived in mainland New Zealand.

But a much smaller, separate population in Stewart Island also persisted.

That group of kakapo numbered only between 3000 and 6000 birds.

The chances of the critically endangered kakapo’s survival could improve through genome...
The chances of the critically endangered kakapo’s survival could improve through genome sequencing of the flightless parrot, conducted recently in New Zealand and Sweden. PHOTO: STEPHEN JAQUIERY
The research, reported this week in Cell Genomics, showed that over the past 10,000 years, the smaller, isolated population of Stewart Island kakapo lost harmful genetic traits through its lack of genetic diversity.

While some genetic mutations were harmful and made an animal’s chance of survival lower immediately, others could sort of hide in the background.

These "slightly deleterious" mutations could be a protein that did not function as well as another one.

The sequencing showed the smaller Stewart Island population, with less genetic variation, somehow had fewer deleterious mutations than the large mainland population, Prof Robertson said.

The genetic variation of the birds now is a major consideration for conservationists.

When the number of kakapo crashed to just 51 birds, in 1995, there were 50 from the Stewart Island group, and a single male, known as Richard Henry, left from the mainland.

Richard Henry died about 10 years ago, Prof Robertson said.

But his three offspring had been important in growing the number of kakapo, now about 200 individuals.

Conservationists incorporated Richard Henry’s genes into the kakapo gene pool, to make sure the animals were not overly inbred.

But conservationists needed to understand that Richard Henry had bad genetic variances, as well.

There were deleterious mutations in his mainland DNA that the Stewart Island population did not have, Prof Robertson said.

Stockholm University researcher Dr Nicolas Dussex said even though the kakapo was now one of the most inbred and endangered birds in the world, it had far fewer harmful mutations than expected.

And it was inbreeding among the Stewart Island birds up to 10,000 years ago that might have helped the removal of those harmful mutations, he said.

hamish.maclean@odt.co.nz

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