Kākāpō lost harmful mutations due to inbreeding

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Neil Fitzgerald
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Kākāpō lost harmful mutations due to inbreeding

Postby Neil Fitzgerald » Sat Sep 11, 2021 9:42 am

Came across this in other media a few days ago but haven't yet been able to find the original paper. It seems kākāpō haven't done too badly considering the bottleneck.

https://www.rnz.co.nz/news/national/451 ... -mutations
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Steps
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Re: Kākāpō lost harmful mutations due to inbreeding

Postby Steps » Sun Sep 12, 2021 10:17 am

That is very interesting.
We had a close contact of some of the top kakariki breeders around the world. Australia (2) Belguim (2) Germany (3) USA (1) Britain (3) Scandinavia (2) . Plus many other minor and pet owners (1000s)
There where strains from 'forced' pairing with little concern of genetic defects resulting in blood lines with heart, liver, bone structure defects... also suspect "attitude" rogue violence.
What we found when re developing the natural 'wild ' blood lines is if we allowed them to choose their own pairs in a large flight, knowing their genetic blood lines , close relatives etc... They naturally close a partner with distanced relationship or no known.
The result being a far better egg to healthy adult ratio (any even suspect defect was always removed from breeding programs.. and often never got much past the weaning stage at most.)
Also bigger birds, significantly bigger, to the extent several of us (around the world) had thought a female was a male.. eventually confirming by the yellow stripe under wings.
They also produced very robust, energetic off spring.. and when left to raise their own young, where excellent parents.. good enough to hatch and raise a sulphur crested.. Picture that in your mind.

It is often ' funny' for want of a better word how amateur breeders have experimented/ known about these things going back at least 50 to 70yrs.. even published... then the scientist make a 'discovery' decades latter of something that is common knowledge.....
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Re: Kākāpō lost harmful mutations due to inbreeding

Postby fras444 » Sun Sep 12, 2021 11:54 am

You also have to think about the last hundreds of thousands of years regarding continual flow of new species of birds into New Zealand from Australia and those interruptions of birds be it a flock or just a couple of pairs who manage to adapt to their new surrounds and breed here who established from just a handful of pairs and what sort of genetic bottleneck they had.. The Barn owl from a single pair through to the handful of Wood duck, a couple of interruptions of Whitefaced Heron and flocks of silvereye. A great cross-section of birds from a pair, a semi-regular flow through to a flock and their evolution of genetics and inbreeding over the last decades or so.
These current breeding species came from either just a couple of pairs through to a small flock or continuous interruptions. It would be interesting to study just how much of an impact to their genetics from I could imagine a significant amount of inbreeding particularly the Barn owl
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Re: Kākāpō lost harmful mutations due to inbreeding

Postby Jake » Sun Sep 12, 2021 11:35 pm

My mind immediately jumps to Swinehoe's Pheasant as an example of extreme inbreeding without too many dangerous genes. The initial capitve population was derived from three birds and were bred for many many decades before "fresh blood" was introduced in the 1960's

I was also reading about Pale-headed Rosellas in Hawaii that were derived from one pair: they initially bred well and founded a good-sized population of many dozen birds before inbreeding lead to their demise

The RNZ kakapo report was good and it now feels a bit ironic that Richard Henry's genes are the ones that the conservationists should be worried about introducing into the population. I'm no geneticist but the mention of good DNA from taxidermied specimens made me hopeful in a Jurassic Park kind of way
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Re: Kākāpō lost harmful mutations due to inbreeding

Postby Steps » Mon Sep 13, 2021 9:24 am

What has been a critical point with kakariki captive inbreeding, has been the difference between a lot of breeders and a handful. Unfortunately some breeders are searching for a result (and/or the profit) selective breeding to a given end result.. be it sale numbers or mutation.
A handful if it is breed able for the end result , it is allowed to live or even given the support to live long enough to breed
Others, Even if suspect some sort of defect, it is removed from any program.
Pretty much what happens in nature.
What worries me a little, is when flocks, in very large flights, are just left to their own to breed, without the predators .. including natural parasites, do the weak/ defective have a better chance to survive to their 1st breeding batch?
Captive breeding has caused certain dog/ cat and many other animal species/breeds to now inherently have heart, bone , liver etc defects.
From the many examples given in posts above, the common link to healthy population from a small gene pool is the unbending 'hardness of nature its self, over the 'give the heart a rub' in many captive populations.
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Re: Kākāpō lost harmful mutations due to inbreeding

Postby Boris » Mon Sep 13, 2021 11:07 am

There is a belief among southern birders that Kakapo were transferred to Stewart Island around the time of Richard Henry's gallant but failed attempt to provide a sanctuary for them on Resolution Island. There is some basis for the belief -Stewart Island lost all its forest cover during the last glaciation (it would have been reduced to a polar tundra), and afterwards Foveaux Strait was inundated before beech forest could return (its seeds are not spread by birds and couldn't cross the strait). The belief is that kakapo never re-established post-glaciation on Stewart Island either. It would be very interesting to read the DNA study results, because it should be able to tell us something about the origins of the Stewart Is population. If the original paper should turn up, please do direct us to it.
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Re: Kākāpō lost harmful mutations due to inbreeding

Postby Jim_j » Mon Sep 13, 2021 12:57 pm

Yes I was a bit unsure of how this was deduced - the article indicates that Kakapo have been on Stewart Is. for 10,000 years - but can genetics tell how long a species has been in a location?
I guess though it's quite possible that kakapo could have survived in a "tundra" like environment - kiwi must have - or both species were able to re-colonise.

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Re: Kākāpō lost harmful mutations due to inbreeding

Postby SomesBirder » Mon Sep 13, 2021 1:06 pm

Jim_j wrote:Yes I was a bit unsure of how this was deduced - the article indicates that Kakapo have been on Stewart Is. for 10,000 years - but can genetics tell how long a species has been in a location?

It should be possible to estimate divergence dates by way of examining the allelic differences between South Island and Stewart Island specimens.
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Re: Kākāpō lost harmful mutations due to inbreeding

Postby Neil Fitzgerald » Tue Sep 14, 2021 10:20 am

Jim_j
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Re: Kākāpō lost harmful mutations due to inbreeding

Postby Jim_j » Tue Sep 14, 2021 11:35 am

Thanks for posting Neil - interesting article.
Seems to clearly end the speculation that Kakapo were only relatively recently introduced to Stewart Is - and highlights the possible risks of introducing "new" genes into a population.
I guess it may lead to keeping populations separate - pure Stewart Island birds and those birds with mixed parentage - until further research indicates otherwise?

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