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Author Topic:   Genetic 'Bottlenecks' and the Flood
Quetzal
Member (Idle past 4256 days)
Posts: 3228
Joined: 01-09-2002


Message 8 of 59 (16226)
08-29-2002 7:06 AM
Reply to: Message 6 by John
08-29-2002 5:23 AM


There IS evidence from at least one species of a genetic bottleneck around (very roughly) the right approximate timeframe. The cheetah (Acinonyx jubatus) is every conservation biologists' favorite example. The bottleneck equated to a reduction of the species to less than seven (some people claim a single pregnant female) individuals. I wonder if this corresponds to the cheetah being put on the ark as 7 specimens? Anyway, cheetahs are some 97% genetically monomorphic(the same as genetically “pure” strains of lab mice). The bottleneck is variously dated from a low of 4000 ya to 10-12,000 ya. The latter figure is probably most accurate. The point, of course, is that something similar MUST be observed in all/nearly all organisms for the massive genetic bottleneck represented by the ark to be even remotely possible.

Here’s a good on-line discussion of the ~10k date
Menotti-Raymond, M. and O’Brien, S.J. 1993. Dating the genetic bottleneck of the African cheetah. PNAS 90.

There are several other organisms that exhibit evidence of more recent genetic bottlenecks, including the Canadian grizzly (see, Implications of preliminary genetic findings for grizzly bear conservation in the central canadian rockies), the northern elephant seal, the baleine whale, florida panther, Illinois prairie chicken, black-footed ferret, etc. However, as would be expected by a standard evolutionary explanation, these bottlenecks are widely separated in time and wildly variable in causation – meaning there’s no way possible to attribute the collection of bottlenecks to a single, one-year-long point event like a global flood. There’s lots of good info in “Conservation Biology” and “Conservation Ecology” journals, as well as all over the web if anyone's interested in this issue (which has significant implications for conservation, preservation, and reintroduction of species). A fascinating topic.

[edited for grmayr an speeling]
[edited again to fix link]
Fixed 2nd link (You missed one, Q) - Adminnemooseus

[This message has been edited by Quetzal, 08-29-2002]

[This message has been edited by Quetzal, 08-30-2002]

[This message has been edited by minnemooseus, 09-20-2002]


This message is a reply to:
 Message 6 by John, posted 08-29-2002 5:23 AM John has not yet responded

Replies to this message:
 Message 9 by Me, posted 08-29-2002 11:53 AM Quetzal has not yet responded
 Message 10 by Mammuthus, posted 08-29-2002 12:25 PM Quetzal has responded

  
Quetzal
Member (Idle past 4256 days)
Posts: 3228
Joined: 01-09-2002


Message 14 of 59 (16290)
08-30-2002 4:24 AM
Reply to: Message 11 by John
08-29-2002 12:26 PM


Thanks John. Appears I had an extra "http://" in there.

This message is a reply to:
 Message 11 by John, posted 08-29-2002 12:26 PM John has responded

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 Message 19 by John, posted 09-20-2002 10:07 PM Quetzal has not yet responded

  
Quetzal
Member (Idle past 4256 days)
Posts: 3228
Joined: 01-09-2002


Message 15 of 59 (16293)
08-30-2002 5:15 AM
Reply to: Message 10 by Mammuthus
08-29-2002 12:25 PM


quote:
Originally posted by Mammuthus:
Hi Quetzal,
I am aware of the more recent bottleneck examples as well as much older bottleneck examples i.e. Homo sapiens. Many of my colleagues worked for the WCS (wildlife conservation society) so I got to see lots of seminars on the subject of bottlenecks. I had thought Steve O'Brien had put the cheetah bottleneck in recent historical times with one single breeding pair owned by a Maharaja who kept exotic pets and bred the cheetahs (I could be wrong...I read it somewhere about 12 years ago). But an example of a bottleneck really spot on dating to the mythical flood has not been demonstrated to my knowledge.

Actually, you're not wrong. O'Brien's original hypothesis, based on nuclear DNA fingerprinting (around 1983, IIRC) showed a bottleneck about 200-300 years ago. The more recent paper I cited shows the older age, based around comparisons between two subspecies using mtDNA and VNTR divergeance. O'Brien's done a lot of work with cheetahs. Interestingly, the satellite DNA comparisons showed that the nuclear DNA tests were valid as well - indicating the cheetah has undergone two bottlenecks! Given the rapid reduction in cheetah populations today, assuming they survive at all in the wild, future scientists will likely find evidence of a third bottleneck dated around this past Tuesday . It's not a CITES I species for nothing...

quote:
Me, however, is very correct in saying that creationists with no background in biology, genetics, or any other science will say that the methods used for determining bottlenecks or lack thereof are wrong so in effect it does not matter. On the other hand I am very certain if an example dating to the mythical flood were found for
even one species of landsnail the creationists would jump up and down about how the same methods they don't believe in vindicate their position

Totally agree. You've both got it right, that's for sure. In fact, I'm rather surprised the creationists HAVEN'T used the cheetah as "proof" of the flood. Maybe the whole bottleneck thing is too esoteric. Or maybe since it's 10k rather than 4k it isn't close enough to make sense. I should email wmscott - it's right on his timeline. (cackles evilly)


This message is a reply to:
 Message 10 by Mammuthus, posted 08-29-2002 12:25 PM Mammuthus has not yet responded

Replies to this message:
 Message 16 by Me, posted 09-02-2002 7:05 AM Quetzal has responded

  
Quetzal
Member (Idle past 4256 days)
Posts: 3228
Joined: 01-09-2002


Message 17 of 59 (16415)
09-02-2002 9:53 AM
Reply to: Message 16 by Me
09-02-2002 7:05 AM


[QUOTE]Originally posted by Me:
I think we have established a new view on living conditions in the Ark with as much assurance as the creationists usually work with. We have now 'proved' that the Ark was launched, but that the predators got out of control and ate all the specimens, leaving a single cheetah pair surviving. They probably climbed the mast while the carnage was taking place below, and ate all the monkeys. Perhaps we could start our own religion on the strength of this astounding insight![/B][/QUOTE]

That is a seriously good idea! The only problem I see is showing how one pair of cheetahs "microevolved" into the 11+ million species of life (including plants) alive today in only 4000 years. Oh, why not? It works for the creationists...


This message is a reply to:
 Message 16 by Me, posted 09-02-2002 7:05 AM Me has not yet responded

Replies to this message:
 Message 18 by Mammuthus, posted 09-02-2002 10:21 AM Quetzal has not yet responded

  
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