D
David Brown
Guest
On 01/02/2022 17:04, jlarkin@highlandsniptechnology.com wrote:
No, it is not. Near-sighted does not mean you are better at seeing
close-up than \"perfect\" sight, it means you are worse at seeing far
away. It has no upside.
What, exactly, do you think I wrote that contradicts Wikipedias pages
here? Either you misread me, or you misread Wikipedia, or you failed to
put two and two together here.
On Tue, 1 Feb 2022 16:52:11 +0100, David Brown
david.brown@hesbynett.no> wrote:
On 01/02/2022 16:35, jlarkin@highlandsniptechnology.com wrote:
On Tue, 1 Feb 2022 11:22:29 +0000, Jeff Layman
According to <https://www.who.int/data/gho/data/themes/malaria>, in 2017
there were 219 million cases of malaria globally, leading to 435,000
deaths. In other words, a death rate of about 0.2%. According to
https://en.wikipedia.org/wiki/Sickle_cell_disease>, in 2015 the death
rate from sickle cell disease was about 2.6% (114,800 in 4.4 million
cases). Figures vary according to the source, but overall it appears
that the death rate from sickle cell disease is about 10 times that of
malaria. So although it might help to stop you dying from malaria, you
are more likely to die from other causes.
I was surprised by these figures, and would be pleased to find I\'ve got
them wrong and sickle-cell disease really does result in a lower death
rate than malaria.
One copy of the sicle gene is advantageous against malaria. That means
it benefits many people without causing illness.
If that were not so, the sickle gene would be eliminated by evolution.
Yes, just as the gene mutations for short-sightedness have been
eliminated by evolution since they have no benefits but cause problems.
I\'m near-sighted. It\'s a huge advantage for me.
No, it is not. Near-sighted does not mean you are better at seeing
close-up than \"perfect\" sight, it means you are worse at seeing far
away. It has no upside.
Oh, wait, it turns out that evolution is not quite that simple. Perhaps
there isn\'t a \"guiding intelligence\" after all?
Evolution has complex interactions. It is /not/ \"survival of the
fittest\". Natural selection selecting particular advantageous traits
works faster than for deselecting disadvantageous traits (this is a
result of the randomness and selection pressure).
Now, it might well be that the benefits of a single copy of the sickle
gene outweigh the disadvantages of having two copies - I don\'t know the
figures. But it is most certainly not guaranteed by evolution. Nor is
there the remotest guarantee that the sickle gene mutation is the \"best\"
solution - it could just as well be the case that a different mutation
would have given better protection against malaria with fewer
side-effects, but random chance has given people this one.
You can argue with Wikipedia on that one. Maybe it\'s a coincidence
that the sickle gene is common in places with mlaria.
What, exactly, do you think I wrote that contradicts Wikipedias pages
here? Either you misread me, or you misread Wikipedia, or you failed to
put two and two together here.