Hi Jeff

Jeff van Hout Wrote:
-------------------------------------------------------
>
> First of all she will have to show "how a gene
> might increase blood oxygen levels, or how high
> oxygen levels in the mother might help her
> children survive".
>


I'm not sure that that is neccessary. We have no idea how genes lead to function in the majority of cases. More significant to me is the fact that they have assumed;

1) Degree of light light absorbed in fingers is due purely to the amount of oxygen in blood. I guess the paper itself would have dealt with this but I would have expected things like maybe amount of iron in the haemoglobin to be a factor both in amount of oxygen carried in the blood and the absorbtion of light.

2) How do you rule out "non-genetic" factors unless you find the gene itself ? Its an assumption.

3) They set out in the first place to "catch the population there in the act of adapting to the low levels of oxygen". From the news article its difficult to see how they did enough to prove they didn't find what they were looking for just because they wanted to find it.


>
> If evolution was at work, shouldn't the majority
> of the population already have this gene, in stead
> of just 10%?
> (How long is this population present at those high
> altitudes?)
>

No I would disagree with that. Evolution is incredibly slow in general and there could be other factors that lead to survival at low oxygen levels such as a different metabolism rate or a taste for iron rich foods etc etc. If you think about it a new gene that made it easier to absord oxygen from rarer air is not a reason for those with that advanatage to completely replace those without it. That would require some other factor such as a famine which really challenged the survival of the population.


>
> Can she prove that in the past the percentage of
> the population having this gene was significantly
> lower?
>


A good point and related to the fact she has not actually found a specific gene and has therefore not compared it with other populations. Still what she has done is shown that families who absorb light in a certain way through their fingers have less young deaths. It is quite possible that this is genetic and if so it would cause more to survive with this genetic make-up and therefore would be "evolution in action". Without reading her actual paper rather than the news article I'm not sure its possible to really decide how much credibility her theory has.