[_ Old Earth _] Does Christianity defy evolution?

[coelacanth]

By there nature mutations are never beneficial.

One heck of a bold statement. Want to back that up with something?

 

[coelacanth]

Here's an example of a beneficial mutation:

http://en.wikipedia.org/wiki/Nylon-eating_bacteria

 

[ChattyMute]

You're talking about the homozygous recessive form, which is indeed harmful. However, the heterozygous form (one allele for sickle cell, the other normal) prevents malaria, which is what kalvan was speaking of.

There is no form of sickle cell that is desirable.

You just ignored everything I said. There is a form that is desirable. Being heterozygous for it. Being heterozygous doesn't effect your ability to obtain oxygen, but you become resistant to malaria. That is extremely desirable, especially in third world countries where people who are heterozygous can most easily be found.

[quote:70stng1k]
It is a mutation in the CCR5 gene. HIV requires the normal CCR5 gene to enter the host cell. The mutated form of CCR5 has a different genetic code, but appears to function the same, except for the fact that HIV can no longer use it to enter the host cell. Thus, the person with all mutated CCR5 (which you have if you are homozygous recessive) is immune to HIV because HIV cannot enter the host cell to reproduce.
We do not know if someone with the CCR5 gene is immune to bubonic plaugue, but some researchers suggest that on account that it is most prevalent in people of European decent where the black plague was.

I have read a study where people with this mutation were HIV infected. [/quote:70stng1k]
Which study? Because I can almost guarantee you that they were not homozygous recessive, but heterozygous for the gene. You can have the mutation and still be susceptible to HIV. You have to have the mutation in both chromosomes the gene is on to be immune.

 

[coelacanth]

http://www.teachersdomain.org/resource/ ... tionstory/

 

[coelacanth]

http://www.teachersdomain.org/resource/ ... vimmunity/

Watch the video

 

[lordkalvan]

Easily refutable nonsense: the sickle-cell mutation provides those with only one copy of the mutation a high degree of resistance to malaria, an obviously desirable benefit to those living where the disease is endemic;

It's also seen as a huge problem in those that have it, causes death in children and this is why researchers are seeking a cure for it! If it was so beneficial why are people working to eradicate it?!

It's a 'huge problem' for those who have two copies of the mutation. For those with one copy who live in malaria-endemic regions it is a positive advantage. The sickle-cell mutation is therefore an advantageous mutation that confers significant and particular benefits. If malaria can be controlled by other methods, the disadvantages of the mutation become more significant.

Such utter non-sense.

Then why do you suppose the sickle-cell mutation arose and spread if it is such a disadvantageous condition?

[quote:1e83db6n] lactose tolerance allows dairy products to be exploited for food; a mutation in an Italian community near Milan renders those with the mutation immune to atherosclerosis;

As always there is a trade-off. Lactose intolerance leads to calcium deficiency that leads to osteoporosis. Vitamin D deficiency can occur and compound the bone disease.
[/quote:1e83db6n]
I was not addressing the question of lactose intolerance so your point is irrelevant, especially as the mutation responsible for lactose tolerance was the one I was addressing. Lactose tolerance remains a beneficial mutation, as does the mutation which confers immunity to atherosclerosis.

[quote:1e83db6n]a mutant allele on the CCR5 gene offers immunity to bubonic plague and the HIV virus.

Having this "mutation" (if that's what you want to call it) by no means should be seen to suggest that having it will prevent HIV infection. What you are suggesting is simply incorrect and misleading.[/quote:1e83db6n]
1. If it's not a mutation, then what is it? Perhaps you would like to redefine mutation so it describes only deleterious alterations in the gene?

2. Er, yes it does confer effective protection against both HIV-1 and bubonic plague. You should read up on genetic studies of the village of Eyam in Derbyshire. This is obviously a beneficial mutation.

 

[lordkalvan]

Having this "mutation" (if that's what you want to call it) by no means should be seen to suggest that having it will prevent HIV infection. What you are suggesting is simply incorrect and misleading.

No, it's correct. Look it up, there are hundreds of scientific papers out there about it, and it's what led scientists to begin developing CCR5 antagonists to add to the cocktails for AIDS patients.

I looked it up and read a study of people with this gene that had HIV.

The gene does not offer protection against HIV, it is a mutation of the gene that does this, namely CCR5-?32. HIV uses CCR5 (or CXCR4) as a co-receptor to penetrate target cells; all humans have the CCR5 gene, but not everyone has the CCR5-?32 mutation which confers beneficial advantages in respect of HIV.

 

[lordkalvan]

Now all you need is the added rare mutation that is not deleterious.

Which would be unlikely to survive and later become advantageous.

And your basis for this assertion would be what, exactly? How do you imagine that the sickle-cell, lactose tolerance, atherosclerosis immunity and CCR5-?32 mutations survived to become advantageous to those fortunate enough to inherit them if such survival is so unlikely?

 

[lordkalvan]

<crickets>

 

[lordkalvan]

Or perhaps even

http://www.worldwidewords.org/qa/qa-col5.htm ?

 

[lordkalvan]

Well, I guess unsupported assertion is taking an extended vacation.....