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Author Topic:   Iconic Peppered Moth - gene mutation found
JonF
Member (Idle past 168 days)
Posts: 6174
Joined: 06-23-2003


Message 16 of 76 (785370)
06-03-2016 4:36 PM
Reply to: Message 14 by Faith
06-03-2016 5:14 AM


Re: not wierd at all.
Same process exactly, while losing the allele for the white moths.
Little problem there. Whatever genetics produce light moths remains in the population. There are always a few light moths. As the trees' barks get lighter on average (because of the great decrease in pollution allowing increased lichen growth) the population is changing and now there are far more light moths than dark moths.

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JonF
Member (Idle past 168 days)
Posts: 6174
Joined: 06-23-2003


Message 23 of 76 (785382)
06-03-2016 9:22 PM
Reply to: Message 20 by Faith
06-03-2016 7:50 PM


That is evidence that it happened at a time when it was convenient, not that it only happened at a time when it was convenient. I've seen articles discussing how often the mutation happens. There's some reason to believe that it happens a few times a century or so, although I've forgotten the details.
But your original comment can't be addressed without an estimate of how often it happens.

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JonF
Member (Idle past 168 days)
Posts: 6174
Joined: 06-23-2003


Message 30 of 76 (785405)
06-04-2016 8:28 AM
Reply to: Message 29 by jar
06-04-2016 8:22 AM


Re: Yes it's totally weird
Of course it is random just as selection is random
Missing a "not:?

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JonF
Member (Idle past 168 days)
Posts: 6174
Joined: 06-23-2003


Message 43 of 76 (785442)
06-05-2016 8:38 AM
Reply to: Message 42 by Faith
06-05-2016 5:11 AM


Re: Very weird indeed
But exploring the consequences of different scenarios makes it highly improbable this was a mutation
Please explain how you explored the consequences and show how you arrived at your probability estimate.
As if.

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JonF
Member (Idle past 168 days)
Posts: 6174
Joined: 06-23-2003


Message 49 of 76 (785463)
06-05-2016 1:21 PM
Reply to: Message 47 by Faith
06-05-2016 1:01 PM


Re: Yes it's totally weird
If you weren't all expecting to find mutations to explain everything, I wonder if you would find them
Yes we would, they are unmistakably present.
If you weren't dedicated to blindness you'd find them too.

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JonF
Member (Idle past 168 days)
Posts: 6174
Joined: 06-23-2003


(3)
Message 71 of 76 (785729)
06-09-2016 1:57 PM
Reply to: Message 69 by Faith
06-09-2016 12:07 PM


You are invited to do the probability calculations, but my rough guess is that to get a specific adaptive trait like a color that matches the background, you'd need something in the thousands or maybe millions of tries before it would show up.
Probably a reasonable guess.
13.5 million humans born each year, each with something on the order of 100 mutations.
16.5 million dogs born each year in the US alone.
Variation, Selection and Time: A Recipe for Biodiversity:
quote:
Many varieties of mice are used as model organisms in laboratory experiments all over the world. As a result mice have been extensively studied, including their mutation rates. Mice have 5 billion DNA bases in their genome and mutation at any one base occurs in about 2 out of every billion bases. There are about 1000 bases in an average gene that can be mutated. Multiply 1000 bases per gene times 2 mutations per billion bases and we get that mutation occurs in a specific gene in about 500,000 individuals. Mice breeding labs have found several mice mutants involving fur color traced a gene called MC1R. There are 10 sites within this gene that if mutated cause the mice’s coat color to be black even if they carry only one copy of the gene (all mice have 2 copies of every gene just as human have 2 copies of every gene — 1 from your mother and 1 from your father).
Table 3. Mice Mutation Rates
s
Mutation Rate2 per 1,000,000,000 bases
Number of sites in MC1R that can be mutated to make a mouse black10
Number of copies of MC1R gene 2
On your answer sheet, calculate the number of mutant mice having a black causing mutation in the MC1R gene that you would expect in 1 billion mice. What are the odds of just one mouse having a black causing mutation in the MC1R gene? [Answer question 7]
Now let’s look at mice population size and birth rates — factors that play a role in the determining how long it takes for one mutation to arise. Pocket mice live in population sizes that range from 10,000 to 100,000 individuals. These mice also have a high reproductive rate — on average 5 babies are born to every female per year. Calculate the number of babies born in a population of 10,000 individuals each year. [Answer question 8]
Multiply answer 8 by answer 7 [Answer question 9]
Your calculations should reveal that in 1,000,000 years, a black-causing mutation will occur independently 1000 times. Every 1000 years you could say that our population of 10,000 pocket mice {i.e. a small population - JonF}hit the black mutation jackpot! How often would a larger population, say 100,000 individuals hit the jackpot? Show your calculations on your answer sheet. [Answer question 10]


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