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Author Topic:   No genetic bottleneck proves no global flood
jar
Member (Idle past 394 days)
Posts: 34026
From: Texas!!
Joined: 04-20-2004


(3)
Message 16 of 140 (662322)
05-14-2012 5:59 PM


Bump for foreveryoung
This is a great thread for you since it is an example of how to do "What if" speculation. It begins by saying "If the Noahic Flood myths are true what must we see?"
You tend to ask just such "What if" questions, but don't take the next step.
For example "What if the speed of light were faster or slower?" Well, the answer there is that we would see the evidence of that in radioactive decay halos and in the stars.
What if the masses were much less than they are today? Then the Earth would be further from the sun and the moon further from the earth and ...
Change leaves evidence and in the case of the Noahic Flood myth, if it did happen as described, then we MUST see the genetic bottleneck signature in EVERY living species of animal, plant, insect and bird.
If someone claims to shoot and hit a target, we can look at the target to see if the hole is there.
No hole, no score.

Anyone so limited that they can only spell a word one way is severely handicapped!

  
Stargaze
Junior Member (Idle past 4106 days)
Posts: 6
Joined: 05-24-2012


Message 17 of 140 (663402)
05-24-2012 9:01 AM


According to AIG they're stating that the human genome shows little genetic variation.
http://www.answersingenesis.org/.../v17/n1/events#fnList_1_7
I'm still in the "novice" category in terms of learning and understanding evolution so please bear with me.
The argument still stands however that even if what AIG says is true...ALL land dwelling organisms should show little genetic variation [bottleneck].

Replies to this message:
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jar
Member (Idle past 394 days)
Posts: 34026
From: Texas!!
Joined: 04-20-2004


Message 18 of 140 (663405)
05-24-2012 9:26 AM
Reply to: Message 17 by Stargaze
05-24-2012 9:01 AM


Welcome home.
Welcome home, pull up a stump and set a spell.
You are correct about all living species (including all land plants) except some fish and water plants showing the same bottleneck signature but there is more. If any of the Biblical Flood myths were true that signature must be very recent in all species.

Anyone so limited that they can only spell a word one way is severely handicapped!

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Wounded King
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Posts: 4149
From: Cincinnati, Ohio, USA
Joined: 04-09-2003


(3)
Message 19 of 140 (663406)
05-24-2012 9:47 AM
Reply to: Message 17 by Stargaze
05-24-2012 9:01 AM


According to AIG they're stating that the human genome shows little genetic variation.
That is reasonable, there isn't a huge amount of human genetic variation compared to some organisms. Unfortunately when AIG try and extend this observation to support their literalist interpretation of genesis things get a lot more iffy.
They state that ..
This study concluded with the possibility that 50 individuals may have founded the entire population of Europe. This evidence is also quite consistent with a historical global flood.
But I find it hard to interpret a severe bottleneck with a population size of 50, overlooking the fact that the paper actually talks about 'effective' population size which is often a much lower value than the actual population (Reich et al., 2001), giving rise to the northern european human population between 15,000 to 50,000 years ago as consistent with an actual population size of 8 people giving rise to the entire human population of the world ~4000 years ago.
TTFN,
WK

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Coyote
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Posts: 6117
Joined: 01-12-2008


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Message 20 of 140 (663409)
05-24-2012 10:47 AM
Reply to: Message 19 by Wounded King
05-24-2012 9:47 AM


No bottleneck
In addition to the lack of a genetic bottleneck, we have the opposite--continuity of many haplogroups across the time period when the flood is claimed to have occurred (ca. 4,350 years ago).
By this I mean we have in most areas of the world continuity of haplogroups that existed prior to 4,350 years ago to dates after 4,350 years ago.
One example (of many): A skeleton from a cave in southern Alaska was dated to 10,300 years ago. That skeleton had haplotype D4h3. That same haplotype was found in a number of living individuals, showing that there was no depopulation during the past 10,300 years.
The presence of many of these examples of continuity is evidence that there was no global flood with the time periods covered.

Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.

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Stargaze
Junior Member (Idle past 4106 days)
Posts: 6
Joined: 05-24-2012


Message 21 of 140 (663435)
05-24-2012 4:10 PM


I have a question. Is there more than one way to "detect" a genetic bottleneck? Or can you only figure this out by comparing one species to another, like they did with the elephant seal example?

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 Message 25 by Dr Adequate, posted 05-29-2012 6:01 PM Stargaze has not replied

  
Taq
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Message 22 of 140 (663437)
05-24-2012 4:17 PM
Reply to: Message 21 by Stargaze
05-24-2012 4:10 PM


I have a question. Is there more than one way to "detect" a genetic bottleneck? Or can you only figure this out by comparing one species to another, like they did with the elephant seal example?
I'm not an expert on population genetics, but I think all you would really need is:
1. The mutation rate.
2. Genetic variation within the population.
3. Stretches of genomic DNA that are not under strong selection (e.g. pseudogenes).

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jar
Member (Idle past 394 days)
Posts: 34026
From: Texas!!
Joined: 04-20-2004


(1)
Message 23 of 140 (663438)
05-24-2012 4:24 PM
Reply to: Message 21 by Stargaze
05-24-2012 4:10 PM


A cat of different spots ...
There are other indicators that were seen even before we could do the detailed genetic sampling that is possible today. Consider something as simple as a skin graft. Now with humans, a skin graft will almost always get rejected unless it is from a very closely related individual, often a twin. But in Cheetahs, skin grafts from just about any other cheetah will work on any other cheetah. It was only once we developed a method of examining the genetics that we understood why.

Anyone so limited that they can only spell a word one way is severely handicapped!

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jar
Member (Idle past 394 days)
Posts: 34026
From: Texas!!
Joined: 04-20-2004


Message 24 of 140 (664183)
05-29-2012 5:36 PM


Bump for foreveryoung
Just a bump to help foreveryoung in his journey.

Anyone so limited that they can only spell a word one way is severely handicapped!

  
Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 25 of 140 (664186)
05-29-2012 6:01 PM
Reply to: Message 21 by Stargaze
05-24-2012 4:10 PM


Well, you look at the size of the population and the amount of genetic diversity within it. In equilibrium (i.e. if the population has been about the same size for a long period of time) the diversity will be proportional to the population size --- there'll be a certain quantity of diversity such that the production of new variants by mutation is just balanced by the elimination of variation by genetic drift.
If there's markedly less diversity than that, this indicates a recent bottleneck.

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Tangle
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From: UK
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Message 26 of 140 (720295)
02-21-2014 11:54 AM


A comment on the radio just prompted me to make a proper scientific prediction.
The comment was that Australia's epidemic population of rabbits are descended from just 13 ( some sources say 24) rabbits in 1859.
There will therefore be a distinct bottleneck - after all, that's only 150 or so years ago.
In the spirit of declaring all results of hypothesis testing even if they disprove it, I offer this:
Abstract
The well documented historical translocations of the European rabbit (Oryctolagus cuniculus) offer an excellent framework to test the genetic effects of reductions in effective population size. It has been proposed that rabbits went through an initial bottleneck at the time of their establishment in Australia, as well as multiple founder events during the rabbit's colonization process. To test these hypotheses, genetic variation at seven microsatellite loci was measured in 252 wild rabbits from five populations across Australia. These populations were compared to each other and to data from Europe. No evidence of a genetic bottleneck was observed with the movement of 13 rabbits from Europe to Australia when compared to French data. Within Australia the distribution of genetic diversity did not reflect the suggested pattern of sequential founder effects. In fact, the current pattern of genetic variation in Australia is most likely a result of multiple factors including mutation, genetic drift and geographical differentiation. The absence of reduced genetic diversity is almost certainly a result of the rabbit's rapid population expansion at the time of establishment in Australia. These results highlight the importance of population growth following a demographic bottleneck, which largely determines the severity of genetic loss.
Just a moment...
So no bottleneck. And the rabbits are still rabbits, damn it.
By the 1920s, less than 70-years since its introduction, the rabbit population in Australia ballooned to an estimated 10 billion, reproducing at a rate of 18 to 30 per single female rabbit per year. The rabbis started to migrate across Australia at a rate of 80 miles a year. After destroying two million acres of Victoria's floral lands, they traversed across the states of New South Wales, South Australia, and Queensland. By 1890, rabbits were spotted all way in Western Australia.
They introduced myxomatosis and knocked out about 90% and continue to trap and shoot them so the levels are nowhere near what they where in 1920s but there are still hundreds of millions.
ps Faith, note that genetic diversity was not lost by isolation - in this case at least.

Life, don't talk to me about life - Marvin the Paranoid Android
"Science adjusts it's views based on what's observed.
Faith is the denial of observation so that Belief can be preserved."
- Tim Minchin, in his beat poem, Storm.

Replies to this message:
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NosyNed
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Posts: 8996
From: Canada
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Message 27 of 140 (720304)
02-21-2014 1:03 PM
Reply to: Message 26 by Tangle
02-21-2014 11:54 AM


Bottleneck
note that genetic diversity was not lost by isolation - in this case at least.
So the arc coulda happened and not shown a bottleneck?

This message is a reply to:
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Tangle
Member
Posts: 9489
From: UK
Joined: 10-07-2011
Member Rating: 4.9


Message 28 of 140 (720306)
02-21-2014 1:16 PM
Reply to: Message 27 by NosyNed
02-21-2014 1:03 PM


Re: Bottleneck
nosyned writes:
note that genetic diversity was not lost by isolation - in this case at least.
So the arc coulda happened and not shown a bottleneck?
Well the rabbits certainly could have been on the ark and not show a bottleneck - according to these findings. Speed of reproduction and an empty ecosystem seems to be a big consideration.
Animals with slower reproduction, say elephants, could be different.

Life, don't talk to me about life - Marvin the Paranoid Android
"Science adjusts it's views based on what's observed.
Faith is the denial of observation so that Belief can be preserved."
- Tim Minchin, in his beat poem, Storm.

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RAZD
Member (Idle past 1405 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 29 of 140 (720308)
02-21-2014 1:31 PM
Reply to: Message 28 by Tangle
02-21-2014 1:16 PM


Re: Bottleneck
Well the rabbits certainly could have been on the ark and not show a bottleneck - according to these findings. Speed of reproduction and an empty ecosystem seems to be a big consideration.
13 is rather larger than 2 for starters, and it would also depend on the male\female mix (1 male to 12 females, mates with each one etc), although one would expect a founder effect unless ...
Second -- did the introduced rabbits from domesticated rabbit stock ... so they would already have reduced genetic variations compared to all rabbits ... and then compared back to that stock? If so I would not expect much change -- especially if there is no selection pressure to change.

we are limited in our ability to understand
by our ability to understand
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This message is a reply to:
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Tangle
Member
Posts: 9489
From: UK
Joined: 10-07-2011
Member Rating: 4.9


Message 30 of 140 (720309)
02-21-2014 1:37 PM
Reply to: Message 29 by RAZD
02-21-2014 1:31 PM


Re: Bottleneck
It would help if someone with access to the full paper and some actual knowledge of genetics (ie not me gave it a read through and translated for us.
On the face of it though, it looks to me like Jar's hypothesis is nfg.

Life, don't talk to me about life - Marvin the Paranoid Android
"Science adjusts it's views based on what's observed.
Faith is the denial of observation so that Belief can be preserved."
- Tim Minchin, in his beat poem, Storm.

This message is a reply to:
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