Re: Concerned about ICC reference

On May 18, 9:28 pm, Lorentz <drosen0...@xxxxxxxxx> wrote:
On May 18, 12:55 pm, Bloopenblop...@xxxxxxxx wrote:

Hello all. On the index to creationist claims, underhttp://www.talkorigins.org/indexcc/CB/CB101.html, Mark Isaak citeshttp://content.nejm.org/cgi/content/short/346/20/1513asan example of
a beneficial mutation. But is this really beneficial? It indeed
strengthens the bones but causes a deformity in the mandible.

The article doesn't say that it caused a deformity in the
mandible. What it said was a "wide and deep" mandible.
"We performed genetic and biochemical analyses of a kindred with an
autosomal dominant syndrome characterized by high bone density, a wide
and deep mandible, and torus palatinus."

This may be a quibble. However, my suspicion is that this type of
variation could be useful in some environments and harmful in others.
Human beings have a wide variety of diets. And in fighting, some
people bite each other. And before there was mass travel, the
difference between different cultures was even bigger.

The idea behind speciation isn't that variations come in either
beneficial or detrimental form, but that the variations in the long
run segregate into environments where they are beneficial. I would
need a lot more information on the wide and deep mandible before I
could even guess whether it is a beneficial or a detrimental one.
Like, is the guy going to be a boxer or wine taster? And is the job a
family tradition? Now if you included an actual description of the
misery caused by this terrible affliction, I may be convinced the
Creationists posters were right (only on this one).
[snip]

Well, here's a picture you can view if you're registered to NEJM (it
only takes like 5 minutes free). http://content.nejm.org/cgi/content/full/346/20/1513/F1
..

The full article describes the effect of this autosomal dominance
syndrome thus:

"A total of seven members of the kindred had strikingly elevated age-
and sex-adjusted bone mineral density in the lumbar spine, femoral
neck, and total body, whereas nine had normal bone density at all
sites (Table 1). Phenotypic classification of bone density as either
very high (indicating affected subjects) or normal (indicating
unaffected subjects) was unambiguous. In affected subjects, age- and
sex-adjusted bone density of the lumbar spine was at least 5 SD above
the population mean, and the mean z scores for bone density in the
lumbar spine, femoral neck, and total body were 6.83, 4.42, and 4.78,
respectively. In contrast, none of the unaffected subjects had a z
score at any site that was greater than 2.71, and the mean z scores
for bone density in the lumbar spine, femoral neck, and total body
were 0.40, -0.61, and -0.08, respectively. All affected subjects had
torus palatinus and the striking square jaw; none of the unaffected
subjects had either of these features. None of the affected subjects
had a history of bone fracture.

The pattern of elevated bone density with torus palatinus and a square
jaw was characteristic of autosomal dominant transmission with high
penetrance (Figure 2). The trait was present in successive
generations, affected or obligate-carrier parents had approximately
equal numbers of affected and unaffected offspring overall, and there
was male-to-male transmission. There were four deceased obligate gene
carriers, one of whom (Subject 16) was examined before death and found
to have torus palatinus and the characteristic mandible. Three living
family members (Subjects 17, 18, and 19) did not undergo bone-density
measurements, but they did not have torus palatinus or the
characteristic facies."

Also note this paragraph elsewhere:

"The heterozygous LRP5V171 mutation precisely cosegregated with high
bone density in the kindred (Figure 3B); LRP5V171 is not a simple
polymorphism, since it was absent in 420 control chromosomes from
unrelated, unaffected subjects. The normal glycine residue shows
extraordinary evolutionary conservation (Figure 3D). Glycine is found
at the same position in the fourth blade of the first three propellers
of LRP5 and LRP6 in humans and mice, as well as in the single
propeller of the low-density lipoprotein (LDL) receptor in humans,
mice, rats, pigs, hamsters, and rabbits. Moreover, glycine is also
found at this position in the first propeller of the Drosophila
melanogaster LDL-receptor-related protein homologue, arrow. In
addition, glycine is present at this position in a wide range of other
YWTD propellers, including those in other LDL-receptor-related
proteins, as well as those in the epidermal growth factor precursor,
the very-low-density lipoprotein receptor, and the vitellogenin
receptor in fruit flies and mosquitos (protein sequences are available
at http://www.ncbi.nlm.nih.gov/entrez). The evolutionary conservation
of this glycine residue is strong evidence of the functional
importance of its mutation in our kindred."

Anyway, I decided to point this out here since TO Archive feedback is
down. Is there a better place to ask this sort of question?

.

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