how do you explain cystic fibrosis? There are multiple mutations that have lead to it and I can't see how it benefits the host. If you have heard of a proven way it does I would like know.
Well, that is not the point. The fact that multiple mutations can lead to it just shows how intricate and complex gene regulatory networks are. But the statistics actually illustrate my point:
Moreover, in the 1980s, people with cystic fibrosis had an average life expectancy of 14 years [source: Disabled World].With modern technology and treatment, however, people with this condition can live well into later adulthood [source: Mayo Clinic]. Some statistics, however, report a much more conservative life expectancy estimate of 35 years [source: Disabled World].In any event, the life expectancy of people with cystic fibrosis is gradually increasing. Approximately 90 percent of infants born with cystic fibrosis will live past a year.Currently, the forecasted life expectancy of babies born today is 40 years old [source: Disabled World]. Infants who have normal pancreas function, however, are expected to life past 50 years old.
It is getting better for those who get the hazardous dice roll during crossover, but it shows the basics of natural selection and illustrates my point.
About 1 in 25 people carries the gene for cystic fibrosis [source: Disabled World].
I am not trying to say that the chances are not high. I did not know the numbers until now and I was expecting less. But the fact that the gene is not much more spread must mean it is not beneficial.
I meant multiple independent mutations in the same gene which causes cystic fibrosis. This shows multiple events where the mutation came about and is leading to a negative selection pressure without dying out within a couple of generations like you mentioned it would.
I am not understanding how those stats support your point. People are living longer with cystic fibrosis because of modern treatment techniques not because of a positive evolutionary change to their genome.
Yes with the principles of natural selection there is going to be a increase in the number of people with the cystic fibrosis gene since more are living to reproduce but as a result it leaves their decedents weaker not stronger genetically.
That was my point exactly. The multiple mutations of the same gene that lead to conditions such as cystic fibrosis are not neutral. They cause an alteration on the phenotype (the condition). If it were not for the advances in medical science, as the stats show with life expentacy at 14 in the 80s, such mutated genomes would hardly be able to reproduce. Hence, natural selection would (in a great enough generation span) take care of it. In the end it's a numbers game influenced by factors we don't clearly understand, yet.
I agree with the principles of natural selection. Whether they are enough to create macro-evolution of organs and appendages is actually up for debate and not proven.
I think that I mainly just took exception to the
Comment since it assumes that conserved mutations are only going to be positive. And then by your definition are no longer neutral genetic drift rather positive mutations so you can't say that genetic drift is positive.
Just curious if you recognize the faith aspect of natural selection that you hold there?