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Fitness Theory and Practice. CrossFit's rationale & foundations. Who is fit? What is fitness?

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Old 07-15-2010, 12:23 PM   #71
Aushion Chatman
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Re: Study finds correlation between C.O.G. and Speed

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Originally Posted by Steven Price View Post
Aushion,
The reason that sickle cell survives in those populations under attack from malaria is that it is the heterozygote that shows resistance to malaria. So the sickle cell genes will never be eliminated from the population. Given, as you say, that the frequency of sickle cell is 0.33, the gene frequency would be the square root of this, or 0.57. The expected number of heterozygotes WITHOUT selection would be 0.57 x 0.42 x 2 (Hardy-Weinberg assumption—see population genetics primer) = 0.48, and the number of homozygotes for the dominant allele would be 0.42 x .42 = 0.18. The point is that the heterozygotes will keep the frequency very high for both genes (alleles). And that is what the data shows. (assuming I didn’t’ mess the arithmetic).

Your quote from Darwin of course represents a “best guess” as of 1871. This theory is not held by ANYONE today; however just as an fyi, he also posited that Homo sapiens arose in Africa, which has since been validated, and was counter to the prevailing theory at the time, which was the site of origin was in Indonesia.

The fact of the matter is that data shows that skin color is statistically associated with many other genetic differences (1000's). See below as an example:

http://en.wikipedia.org/wiki/Human_genetic_variation

You will note that if you look at the chart on the right side that skin color would overlay pretty well this distribution. There are exceptions, but not many.

In fact self-reporting of “race” by patients is now seen as a major step forward for the treatment of hypertension, Tay Sachs, prostate cancer, and diabetes.

I fail to see why recognizing race is "lazy" science. It is rooted in 100 years of study. Humans are animals, with an evolutionary history. Human populations have had different histories. Race is just a lumping of populations--just a helpful vocabulary word that integrates over well established differences. Why throw out useful words?
Well this is starting to get circular so I may just need to do more research and get with you guys offline.

But I'll say again, to which category would my son check in the race box...this is why it is lazy..does my son show a trait for hypertension closer to "black race" or "white race"...It is clearly more accurate to get a picture of genetic predisposition. There are numerous children who are labeled, "black race" which is a misnomer...if race is simply to mean color that is fine, but then we can't use race for medicine...that simply doesn't work.

if race is to mean nationality that too is fine, but I believe it is too ingrained in our psyche to mean color for us to be able to use it to mean nationality or to describe a community.

When you say medicine is making great strides with people checking the race block, don't you mean in the USA ONLY?
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Old 07-15-2010, 12:25 PM   #72
Jamie J. Skibicki
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Re: Study finds correlation between C.O.G. and Speed

"why is dark skin a genetic advantage near the equator (in the tropics)...?"

Uv protection. Even with a tan, I can't spend a long time out in the sun. And that at 42 degrees where the sun is less intense. Also, excessive vitamin D is as much of a problem as too much. Not a huge difference, but it doesn't need to be.

I think we are confusing the scientific definition of race with the colloquial definiton of race much like people do with work. Aush, I think it's the use of the word race that bothers. From wikipedia

"In biology, races are inbreeding groups within the same species with relatively minor morphological and genetic differences."

So your earlier remark about black coming from gorillas, asians coming from oranatangs etc, would be different species, not races.
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Old 07-15-2010, 12:49 PM   #73
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Re: Study finds correlation between C.O.G. and Speed

[quote=Aushion Chatman;811478] "Well this is starting to get circular so I may just need to do more research and get with you guys offline."

I think you need to examine the cited websites, especially

http://en.wikipedia.org/wiki/Human_genetic_variation wfs

And pay particular attention to the colored boxes in the chart on the right hand side. Based on 1000's of genetic differences. Every study of this type continutes to show the same pattern. We are NOT finding a hodge podge of genetic differences--they fall in to very clear patterns. "Pattern" = "race."

To say the concept of race is not relevant to medicine is just not correct. If you are aware of any peer reviewed literature that supports this notion, please send to me. This is an active area of research/discussion in the field of medicine, as well as policy development, so any counter evidence would be useful.
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Old 07-15-2010, 12:55 PM   #74
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Re: Study finds correlation between C.O.G. and Speed

Steven,

I think Aush's problem, and I'm guessing here, is the correlation of color to race.
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Old 07-15-2010, 01:11 PM   #75
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Re: Study finds correlation between C.O.G. and Speed

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Steven,

I think Aush's problem, and I'm guessing here, is the correlation of color to race.
Correct, I have no problem with race if it means nationality or community group. But race simply as skin color is where I have the problem as that is not accurate. The line gets gray (no pun intended) very quickly.
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Old 07-15-2010, 01:19 PM   #76
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Re: Study finds correlation between C.O.G. and Speed

Jaime,

But of course skin color IS a good APPROXIMATION of race.

I invite anyone to go to the website given above:

http://en.wikipedia.org/wiki/File:Populations.png

Develop a ranking of melanin content of their own choosing, and overlay this chart with their own ranking. I think it will be very obvious that skin color and the pattern in this chart will show a high degree of correlation. The one outlier is New Guineans and Australians.

No surprises here?
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Old 07-15-2010, 01:26 PM   #77
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Re: Study finds correlation between C.O.G. and Speed

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Originally Posted by Jamie J. Skibicki View Post
"why is dark skin a genetic advantage near the equator (in the tropics)...?"

Uv protection. Even with a tan, I can't spend a long time out in the sun. And that at 42 degrees where the sun is less intense. Also, excessive vitamin D is as much of a problem as too much. Not a huge difference, but it doesn't need to be.

I think we are confusing the scientific definition of race with the colloquial definiton of race much like people do with work. Aush, I think it's the use of the word race that bothers. From wikipedia

"In biology, races are inbreeding groups within the same species with relatively minor morphological and genetic differences."

So your earlier remark about black coming from gorillas, asians coming from oranatangs etc, would be different species, not races.
yes, that is what I have the problem with Jamie, we don't use race as it is defined...

I still say that skin tone being darker in the tropics is a VERY weak reason for (especially) humans to have selected darker skin in those regions. Even animals with limited brain capacity (lizards, snakes) have the survival capacity to dig or seek shade when the sun is blazing. I can't see hot summer days being the reason there is such a disparity in skin color observed in certain regions.

Same with the lack of Vitamin D, it is a cute way to say lighter skin is advantageous in cooler regions, but really how advantageous...enough that the darker skin people in those regions died off in the past or were not selected? Are we sure a vitamin d deficiency could yield that dramatic of a result? Did humans instinctively choose lighter mates in those regions?

Let's not also forget that Vitamin D can be obtained through food intake, fish, eggs, mushrooms, all naturally contain vitamin d, so you don't just have to get it from your skin's production. From Wiki on Vitamin D we see that recommended dialy Vitamin D intake levels hover at 200 IU, 1 gram of catfish provides ~425 IU. So it isn't necessarily so that food intake is insufficient.
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Old 07-15-2010, 01:34 PM   #78
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Re: Study finds correlation between C.O.G. and Speed

Aush

The USDA recommend intake is 400 IU per day. that is to prevent rickets. Optimal intake is closer to 10,000 iu per day (thats how much the body makes in the clime it is adapted for).
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Old 07-15-2010, 01:48 PM   #79
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Re: Study finds correlation between C.O.G. and Speed

isn't preventing rickets enough to be "fit"? that is my whole point, why would even 200IU/day mean a whole populace is not selected in certain regions...? that seems a BIG stretch statistically.
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Old 07-15-2010, 01:52 PM   #80
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Re: Study finds correlation between C.O.G. and Speed

Does anyone have steven low's paper on vitamin D?

Testosterone levels, sleep, and recovery are all associated with optimal vitamin d levels.
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