Got short thighs? Your diabetes risk may be high

zakur · 7th March 2003, 08:37 AM

Quote:

Got short thighs? Your diabetes risk may be high

Having trouble fitting your trousers? Maybe you are at risk of diabetes, with new U.S. research identifying short thighs as a possible marker for the disease.

Research presented today at the 43rd Annual Conference on Cardiovascular Disease Epidemiology and Prevention in Miami shows that people with short upper legs are more likely to have glucose intolerance or diabetes - particularly if they are white and female.

tim · 7th March 2003, 11:43 AM

OK, I have diabetese and short thighs. I guess that proves it!

DrChinese · 13th March 2003, 08:51 PM

Isn't this just a modern version of phrenology?

http://pages.britishlibrary.net/phrenology/

No causal relationship postulated. Which comes first? The short thighs or the increased risk of diabetes? Both related to the same cause? Like there is a gene called "increased risk of diabetes."

The study postulates the existence of some yet unidentified third something which is somehow relevant. However, I have this to say for the study's results: Spurious correlations - no matter how strange - are scientifically useless. So is this study. Either there is a causal relationship which was hypothesized and documented by the study; or not. Instead we ended up with the authors of the study touting a spurious relationship.

It would be science if they were attempting to prove or disprove the implied hypothesis behind the spurious correlation. So I will state: this study adds absolutely zero to our understanding of science.

Penn and Teller have a word for studies like this.

BillyJoe · 14th March 2003, 04:02 AM

OK, I don't have diabetes and don't have short thighs. I guess that confirms it!

tim · 14th March 2003, 09:25 AM

Quote:

Originally posted by BillyJoe
OK, I don't have diabetes and don't have short thighs. I guess that confirms it!

Ah, if only other scientific theories were so easily dealt with. Next!

PygmyPlaidGiraffe · 14th March 2003, 02:54 PM

from the same article:

"When the researchers adjusted for other risk factors - age, body weight, family history of diabetes, education, income, physical activity levels and lung function - they found the correlation did not exist for blacks and men.
However, white women and Mexican-American women still showed the" CORRELATION". White women were 19% more likely, and Mexican-American women were 13% more likely to have diabetes for each centimetre their thighs were shorter than the average.
The average ULL for men and women with normal glucose tolerance was 40.2 cm, compared to 39.1 cm for those with impaired glucose tolerance and 38.3 cm for the diabetic group."

I can show a correlation between people who own blue tea cups owning blue tea pots given a large enough sample. Owning a blue tea cup will not ensure that an individual will own a blue tea pot. Hmmmm, teeeeeeea.

IMO the sad part of correlation studies are that people may feel that they can do nothing (change their diet, or exercise for example to elavate metabilism) as they are screwed anyways (in this example, by something out of their control, like genes).

Quote-

"Its the correlation carnival train! Get on quick before it pulls away! I missed it back in the Veldt and as a result I am (shamefully) correlationaly challenged. - PPG, 2003

PygmyPlaidGiraffe · 14th March 2003, 03:11 PM

Quote:

Originally posted by DrChinese
Isn't this just a modern version of phrenology?

Penn and Teller have a word for studies like this.

Please induldge us Doc... that word would be? I enjoy Penn and Teller but am not too familiar with their unabridged glossary.

I wonder what words George Carlin would ascribe to these studies.

Quote-

It's the correlation band wagon! Get on quick before it pulls away! I missed it and as a result I am (shamefully) correlationly challenged. - PPG, 2003

DrChinese · 14th March 2003, 04:30 PM

Sorry, I should have explained. Phrenology was the "science" that demonstrated that human behavior was related to the physical shape of your skull. There were detail maps, etc. I hope this explanation does not offend any practicing phrenologists out there, but suffice it to say that this was debunked a long time ago.

My point is that it is 100% totally useless to measure a correlation between thighs and diabetes if it is spurious. Realistically, you could never rely on it to yield useful information.

The obvious example is: if I have short thighs, will I get diabetes? A meaningful question cannot be answered from spurious correlations, because ultimately you will say: how will my actions be different? Answer: you cannot rely on a diagnosis of short thighs to have you taking medicine for diabetes. You need a medical test to detect diabetes instead.

DrChinese · 14th March 2003, 04:33 PM

[quote]Originally posted by PygmyPlaidGiraffe
[b]

Please induldge us Doc... that word would be? I enjoy Penn and Teller but am not too familiar with their unabridged glossary.

I wonder what words George Carlin would ascribe to these studies.

Quote-

Penn and Teller's series on Showtime is called Bullsh**. And that's what phrenology is.

Houngan · 14th March 2003, 11:25 PM

Folks, while I can't weigh in on whether this particular study is bogus, I have to point out that other such links do exist in the human body.

In particular, there is a clear, proven link between black people, sickle-cell anemia, and malaria resistance. If someone is homozygous recessive with the sickle gene, they are extremely resistant to malaria, but unfortunately in deep trouble re: sickle cell anemia. If they are homozygous dominant, they don't have sickle cell, but are susceptible to malaria. The (formerly) lucky ones were heterozygous, and benefitted from being resistant to malaria without as crushing a burden from sickle-cell anemia.

The many, many traits involved in short thighs might very well be linked to susceptibility to diabetes. Genetics has no political correctness, and myriad ways to make silly associations that are nevertheless true.

H.

BillyJoe · 15th March 2003, 07:48 AM

Quote:

Originally posted by Houngan
If someone is homozygous recessive with the sickle gene, they are extremely resistant to malaria, but unfortunately in deep trouble re: sickle cell anemia. If they are homozygous dominant, they don't have sickle cell, but are susceptible to malaria. The (formerly) lucky ones were heterozygous, and benefitted from being resistant to malaria without as crushing a burden from sickle-cell anemia.

I think your terminology has gone awry.

The gene for sickle cell anaemia is Recessive
This means you have to have both genes affected to have sickle cell anaemia (remember we have two copies of each gene).
If the gene was Dominant, you would need only one gene affected to get the disease.

If you have both genes affected, you are said to be Homozygous for that gene.
If you have only one gene affected, you are said to be Heterozygous for that gene.

If you are Homozygous, you have BOTH sickle cell anaemia AND resistance to malaria.
If you are Heterozygous, you don't have sickle cell anaemia but you do have resistance to malaria.

15th March 2003, 02:47 PM

BillyJoe, isn't that what he said? I don't see where his problem lies. He didn't specifically say that the sickle cell gene is recessive, but I thought it was obvious from what he wrote. Of course, I already knew that to begin with, so if it wasn't obvious I wouldn't have noticed.

Houngan · 15th March 2003, 04:23 PM

Quote:

Originally posted by BillyJoe
I think your terminology has gone awry.

The gene for sickle cell anaemia is Recessive
This means you have to have both genes affected to have sickle cell anaemia (remember we have two copies of each gene).
If the gene was Dominant, you would need only one gene affected to get the disease.

If you have both genes affected, you are said to be Homozygous for that gene.
If you have only one gene affected, you are said to be Heterozygous for that gene.

If you are Homozygous, you have BOTH sickle cell anaemia AND resistance to malaria.
If you are Heterozygous, you don't have sickle cell anaemia but you do have resistance to malaria.

The sickle-cell gene isn't a total dominant gene. There are gradations whether homo or hetero. Many genes and gene complexes produce varied results in between homo dominant and homo recessive.

H.

BillyJoe · 15th March 2003, 10:07 PM

Let's dissect this then....

Quote:

Originally posted by Houngan
If someone is homozygous recessive with the sickle gene, they are extremely resistant to malaria, but unfortunately in deep trouble re: sickle cell anemia.

I have no problem with this....

Sickle Cell Anaemia is a Recessive condition.
Therefore you have to have both genes (ie to be homozygous) for the Sickle Cell gene to have the disease.
You also have malaria resistance by virtue of having at least one Sickle Cell gene.

Quote:

Originally posted by Houngan
If they are homozygous dominant, they don't have sickle cell....

As I said before, Sickle Cell Anaemia is a Recessive condition.
However, if Sickle Cell Anaemia was a Dominant condition, you would have the disease even if you only had one gene (ie if you were heterozygous) for the Sickle Cell gene.
And you would certainly have the disease if you had both genes (ie if you were homozygous) for Sickle Cell anaemia.

Quote:

Originally posted by Houngan
If they are homozygous dominant, they ...... are susceptible to malaria.

Again, Sickle Cell Anaemia is a Recessive not a Dominant condition but, if they were homozygous, they would actually have resistance to malaria not be susceptible to it as you have stated.

Quote:

Originally posted by Houngan
The (formerly) lucky ones were heterozygous, and benefitted from being resistant to malaria without as crushing a burden from sickle-cell anemia.

I have no problem with this.

BillyJoe · 15th March 2003, 10:21 PM

Quote:

Originally posted by Houngan
The sickle-cell gene isn't a total dominant gene. There are gradations whether homo or hetero. Many genes and gene complexes produce varied results in between homo dominant and homo recessive.

You definitely seem to be confused between the meanings of heterozygous/homozygous and Recessive/Dominant.

heterozygous: having only one gene for the condition.
homozygous: having both genes for the condition.

Recessive: need both genes to actually suffer from the condition.
Dominant: need only one gene to actually suffer from the condition.

therefore.....

If you are heterozygous for a Recessive gene, you do not have the condition.
If you are homozygous for a Recessive gene, you do have the condition
If you are heterozygous for a Dominant gene, you have the condition.
If you are homozygous for a Dominant gene, you have the condition.

BillyJoe · 17th March 2003, 03:30 AM

What do you say, Houngan?
I mean I'm no expert. I think my summary is correct but I could be wrong and, if I am, I'd like to know so I don't make a fool of myself again.

PygmyPlaidGiraffe · 17th March 2003, 12:19 PM

Quote:

Originally posted by Houngan
Folks, while I can't weigh in on whether this particular study is bogus, I have to point out that other such links do exist in the human body.

In particular, there is a clear, proven link between black people, sickle-cell anemia, and malaria resistance. If someone is homozygous recessive with the sickle gene, they are extremely resistant to malaria, but unfortunately in deep trouble re: sickle cell anemia. If they are homozygous dominant, they don't have sickle cell, but are susceptible to malaria. The (formerly) lucky ones were heterozygous, and benefitted from being resistant to malaria without as crushing a burden from sickle-cell anemia.

Genetics has no political correctness

H.

A female Anopheles gambiae mosquito feeding on a person could transmit the malaria parasite

perhaps this link could help refresh people's memory about malaria:

U.S. National Library of Medicine and U.S. National Institutes of Health provide info here:

http://www.nlm.nih.gov/medlineplus/e...cle/000527.htm

Quote:

Sickle Cell Disease is much more common in certain ethnic groups affecting approximately one out of every 500 African Americans. Because people with sickle trait were more likely to survive malaria outbreaks in Africa than those with normal hemoglobin, it is believed that this genetically aberrant hemoglobin evolved as a protection against malaria.

The CDC has info regarding malaria and history since the 16th century.

http://www.cdc.gov/ncidod/eid/vol6no1/reiter.htm

I would suggest that weather changes affect the range of the Anopheles. Where Anopheles goes the parisite goes and it can deliver the parisite to human popuations.

Parishes in England kept records of deaths by ague (which, by detailed records of symptoms, parralels observed symptoms of malaria stricken people) over the centuries. A couple of Shakespeare's plays make reference to ague. Ague was associated with marshes/bogs which smell terrible (mal = bad , aria = air).

I have not come across any evidence to suggest that the following train of thought is accurate , but I would imagine that the population in SW England over the centuries would produce individuals with sickle cell anemia.

Bloodwork analysis would have been non-existant of course, and DNA tests of the individuals' remains would be needed to confirm how many people buried in parsihes at certain dates had Hb SS.

I find it very interesting that males would take up residence in the marsh's bogs to make a living "quarrying" peat, a fuel. These men would come into town to find a spouse and sell their peat. More often than not the woman would succumb to ague, but not usually die before producing off-spring.

The man would survive his wife, but in a man-of-the-marsh's life time he may have 2 or more wives (out-living 2 or more of them). The apparently resiliant man could father several children. I am aware the death rate for women was quite high due to many reasons, but quite often the woman would have several symptoms of ague.
Note too that not every man that took up residence in marsh survived long enough to take a wife.

The ague, which has a high possibility of being malaria, would be transfered by mosquitos. It has been verified by historical documentation and research that no less than 5 species of Anopheles were at one time or another present in Southwest England.

As I stated I can not back it up, but the presence of Anopheles and the fact that Anopheles carry the pariste may have allowed the normally non-advantageous HbSS to become more common in indiviaduals with in the population of SW England, particularly among those that lived in the rural, marsh areas. HbSS, as undessirable as it may be to an organism, gives an organism an edge over like organisms that do not have HbSS.

African Americans and "black" African populations today may have a higher proportion of individuals with HbSS, but I doubt that it has to do with a proven link between black people, sickle-cell anemia, and malaria resistance. I would suggest that the presense of Anopheles (which has a range limited due to enviromental and climatic factors which vary significantly over centuries) is more of an indicator as to whether a community has a higher incidence of malaria or HbSS.

How to explain the incidence of HbSS in African Americans? Perhaps it has to do with how many generations affected individuals in a community are removed from their "homeland". Here is where my knowledge would prevent me from speculating how many generations would be needed to result in less individuals in a community from exhibiting HbSS.

Of course, check out the evidence for yourselves, I am not an authority on Anopheles, HbSS, genetics, weather change, or parish burial records from SW England.

Quote-

"It's the correlation band wagon! Get on quick before it pulls away! I missed it back on the veldt and as a result I am (shamefully) correlationly challenged." - PPG, 2003

Houngan · 19th March 2003, 03:52 PM

Quote:

Originally posted by BillyJoe
What do you say, Houngan?
I mean I'm no expert. I think my summary is correct but I could be wrong and, if I am, I'd like to know so I don't make a fool of myself again.

Well, to put it bluntly, you are indeed wrong. You have a firm grasp of total dominance in genetics, but not of partial dominance. Some genes work one way, some work the other.

In this case, folks who are hetero for the sickle gene do have a slight sickle-cell condition, and also malaria resistence. Homo recessive have a much more severe sickle, and homo dominant don't have sickle at all (and are malaria susceptible.)

This is probably due to (and I in no way mean this as a slight) insufficient education. Schools like to present things as broad strokes in early classes, then get into the details later on. So, genetics is often introduced in the form of total dominant genes, so students can learn how to do Punnet squares. Later on, you get into partial dominance, and gene linking. (A good example of which is skin color. Obviously there are many gradations of darkness/melanin content in human skin, and as it turns out, it is dependent on several genes working together.)

So, the short form is that although alleles are a binary system (dom., rec.), for some traits the 01 and 10 result are different than 11 and 00.

H.

BillyJoe · 20th March 2003, 12:41 AM

Houngan,

Perhaps our disagreement is the result of us talking about different phenotypes?
How does this sound?......

Dominant and Recessive refer to phenotype.

If we are talking about the sickle cell phenotype, the inheritance is Dominant....
AA: normal cells
AS: normal cells + sickle cells (so, actually, Codominant)
SS: sickle cells.

If we are talking about the sickle cell anaemia or the sickle cell disease phenotype, the inheritance is Recessive....
AA: no disease
AS: no disease
SS: disease.

If I am way off beam, instead of a lengthy reply perhaps you have a reference.

Houngan · 20th March 2003, 11:45 AM

Christ, Man! Why didn't you say so! I see exactly what you're saying now. I originally thought you didn't understand codominance at all.

I'll take back everything I said; I was unaware that they were two different phenotypes.

H.

BillyJoe · 21st March 2003, 01:53 AM

7th March 2003, 08:37 AM	#1
zakur Illuminator Join Date: Aug 2001 Location: Dayton, OH Posts: 3,265	Got short thighs? Your diabetes risk may be high Quote: Got short thighs? Your diabetes risk may be high Having trouble fitting your trousers? Maybe you are at risk of diabetes, with new U.S. research identifying short thighs as a possible marker for the disease. Research presented today at the 43rd Annual Conference on Cardiovascular Disease Epidemiology and Prevention in Miami shows that people with short upper legs are more likely to have glucose intolerance or diabetes - particularly if they are white and female.
	__________________ "I do not believe in the collective wisdom of individual ignorance." -Thomas Carlyle "That's the problem these days: nobody thinks of the tumors." -steinhenge

13th March 2003, 08:51 PM	#3
DrChinese Muse Join Date: Mar 2003 Posts: 634	Isn't this just a modern version of phrenology? http://pages.britishlibrary.net/phrenology/ No causal relationship postulated. Which comes first? The short thighs or the increased risk of diabetes? Both related to the same cause? Like there is a gene called "increased risk of diabetes." The study postulates the existence of some yet unidentified third something which is somehow relevant. However, I have this to say for the study's results: Spurious correlations - no matter how strange - are scientifically useless. So is this study. Either there is a causal relationship which was hypothesized and documented by the study; or not. Instead we ended up with the authors of the study touting a spurious relationship. It would be science if they were attempting to prove or disprove the implied hypothesis behind the spurious correlation. So I will state: this study adds absolutely zero to our understanding of science. Penn and Teller have a word for studies like this.
DrChinese Muse Join Date: Mar 2003 Posts: 634	__________________ www.DrChinese.com The map is not the territory. - Korzybski.

14th March 2003, 04:02 AM	#4
BillyJoe Penultimate Amazing Join Date: Aug 2001 Location: MOOROOLBARK Posts: 12,539	OK, I don't have diabetes and don't have short thighs. I guess that confirms it!
	__________________ A secular society is one in which no one loses any liberty as a consequence of someone else's religious beliefs. NB Allowing yourself to get led around the nose by a person like Craig is a losing strategy. SH Morality is a social coating around a Darwinian core. JC My joke about freewill: There is no basis for it.

14th March 2003, 04:30 PM	#8
DrChinese Muse Join Date: Mar 2003 Posts: 634	Sorry, I should have explained. Phrenology was the "science" that demonstrated that human behavior was related to the physical shape of your skull. There were detail maps, etc. I hope this explanation does not offend any practicing phrenologists out there, but suffice it to say that this was debunked a long time ago. My point is that it is 100% totally useless to measure a correlation between thighs and diabetes if it is spurious. Realistically, you could never rely on it to yield useful information. The obvious example is: if I have short thighs, will I get diabetes? A meaningful question cannot be answered from spurious correlations, because ultimately you will say: how will my actions be different? Answer: you cannot rely on a diagnosis of short thighs to have you taking medicine for diabetes. You need a medical test to detect diabetes instead.
DrChinese Muse Join Date: Mar 2003 Posts: 634	__________________ www.DrChinese.com The map is not the territory. - Korzybski.

14th March 2003, 04:33 PM	#9
DrChinese Muse Join Date: Mar 2003 Posts: 634	[quote]Originally posted by PygmyPlaidGiraffe [b] Please induldge us Doc... that word would be? I enjoy Penn and Teller but am not too familiar with their unabridged glossary. I wonder what words George Carlin would ascribe to these studies. Quote- Penn and Teller's series on Showtime is called Bullsh**. And that's what phrenology is.
DrChinese Muse Join Date: Mar 2003 Posts: 634	__________________ www.DrChinese.com The map is not the territory. - Korzybski.

7th March 2003, 11:43 AM	#2
tim Lasiorhinus latifrons Combat Division Join Date: Jan 2003 Location: Bedfordshire, UK Posts: 11,329	OK, I have diabetese and short thighs. I guess that proves it!

14th March 2003, 09:25 AM	#5
tim Lasiorhinus latifrons Combat Division Join Date: Jan 2003 Location: Bedfordshire, UK Posts: 11,329	Quote: Originally posted by BillyJoe OK, I don't have diabetes and don't have short thighs. I guess that confirms it! Ah, if only other scientific theories were so easily dealt with. Next!

14th March 2003, 02:54 PM	#6
PygmyPlaidGiraffe Graduate Poster Join Date: Mar 2003 Location: Alberta, Canada Posts: 1,289	from the same article: "When the researchers adjusted for other risk factors - age, body weight, family history of diabetes, education, income, physical activity levels and lung function - they found the correlation did not exist for blacks and men. However, white women and Mexican-American women still showed the" CORRELATION". White women were 19% more likely, and Mexican-American women were 13% more likely to have diabetes for each centimetre their thighs were shorter than the average. The average ULL for men and women with normal glucose tolerance was 40.2 cm, compared to 39.1 cm for those with impaired glucose tolerance and 38.3 cm for the diabetic group." I can show a correlation between people who own blue tea cups owning blue tea pots given a large enough sample. Owning a blue tea cup will not ensure that an individual will own a blue tea pot. Hmmmm, teeeeeeea. IMO the sad part of correlation studies are that people may feel that they can do nothing (change their diet, or exercise for example to elavate metabilism) as they are screwed anyways (in this example, by something out of their control, like genes). Quote- "Its the correlation carnival train! Get on quick before it pulls away! I missed it back in the Veldt and as a result I am (shamefully) correlationaly challenged. - PPG, 2003

14th March 2003, 03:11 PM	#7
PygmyPlaidGiraffe Graduate Poster Join Date: Mar 2003 Location: Alberta, Canada Posts: 1,289	Quote: Originally posted by DrChinese Isn't this just a modern version of phrenology? Penn and Teller have a word for studies like this. Please induldge us Doc... that word would be? I enjoy Penn and Teller but am not too familiar with their unabridged glossary. I wonder what words George Carlin would ascribe to these studies. Quote- It's the correlation band wagon! Get on quick before it pulls away! I missed it and as a result I am (shamefully) correlationly challenged. - PPG, 2003

14th March 2003, 11:25 PM	#10
Houngan Scholar Join Date: Aug 2001 Posts: 116	Folks, while I can't weigh in on whether this particular study is bogus, I have to point out that other such links do exist in the human body. In particular, there is a clear, proven link between black people, sickle-cell anemia, and malaria resistance. If someone is homozygous recessive with the sickle gene, they are extremely resistant to malaria, but unfortunately in deep trouble re: sickle cell anemia. If they are homozygous dominant, they don't have sickle cell, but are susceptible to malaria. The (formerly) lucky ones were heterozygous, and benefitted from being resistant to malaria without as crushing a burden from sickle-cell anemia. The many, many traits involved in short thighs might very well be linked to susceptibility to diabetes. Genetics has no political correctness, and myriad ways to make silly associations that are nevertheless true. H.
Houngan Scholar Join Date: Aug 2001 Posts: 116	__________________ Sum Ergo Cogito.

15th March 2003, 07:48 AM	#11
BillyJoe Penultimate Amazing Join Date: Aug 2001 Location: MOOROOLBARK Posts: 12,539	Quote: Originally posted by Houngan If someone is homozygous recessive with the sickle gene, they are extremely resistant to malaria, but unfortunately in deep trouble re: sickle cell anemia. If they are homozygous dominant, they don't have sickle cell, but are susceptible to malaria. The (formerly) lucky ones were heterozygous, and benefitted from being resistant to malaria without as crushing a burden from sickle-cell anemia. I think your terminology has gone awry. The gene for sickle cell anaemia is Recessive This means you have to have both genes affected to have sickle cell anaemia (remember we have two copies of each gene). If the gene was Dominant, you would need only one gene affected to get the disease. If you have both genes affected, you are said to be Homozygous for that gene. If you have only one gene affected, you are said to be Heterozygous for that gene. If you are Homozygous, you have BOTH sickle cell anaemia AND resistance to malaria. If you are Heterozygous, you don't have sickle cell anaemia but you do have resistance to malaria.
	__________________ A secular society is one in which no one loses any liberty as a consequence of someone else's religious beliefs. NB Allowing yourself to get led around the nose by a person like Craig is a losing strategy. SH Morality is a social coating around a Darwinian core. JC My joke about freewill: There is no basis for it.

15th March 2003, 02:47 PM	#12
rwald Guest Posts: n/a	BillyJoe, isn't that what he said? I don't see where his problem lies. He didn't specifically say that the sickle cell gene is recessive, but I thought it was obvious from what he wrote. Of course, I already knew that to begin with, so if it wasn't obvious I wouldn't have noticed.
rwald Guest Posts: n/a

15th March 2003, 04:23 PM	#13
Houngan Scholar Join Date: Aug 2001 Posts: 116	Quote: Originally posted by BillyJoe I think your terminology has gone awry. The gene for sickle cell anaemia is Recessive This means you have to have both genes affected to have sickle cell anaemia (remember we have two copies of each gene). If the gene was Dominant, you would need only one gene affected to get the disease. If you have both genes affected, you are said to be Homozygous for that gene. If you have only one gene affected, you are said to be Heterozygous for that gene. If you are Homozygous, you have BOTH sickle cell anaemia AND resistance to malaria. If you are Heterozygous, you don't have sickle cell anaemia but you do have resistance to malaria. The sickle-cell gene isn't a total dominant gene. There are gradations whether homo or hetero. Many genes and gene complexes produce varied results in between homo dominant and homo recessive. H.
Houngan Scholar Join Date: Aug 2001 Posts: 116	__________________ Sum Ergo Cogito.

15th March 2003, 10:07 PM	#14
BillyJoe Penultimate Amazing Join Date: Aug 2001 Location: MOOROOLBARK Posts: 12,539	Let's dissect this then.... Quote: Originally posted by Houngan If someone is homozygous recessive with the sickle gene, they are extremely resistant to malaria, but unfortunately in deep trouble re: sickle cell anemia. I have no problem with this.... Sickle Cell Anaemia is a Recessive condition. Therefore you have to have both genes (ie to be homozygous) for the Sickle Cell gene to have the disease. You also have malaria resistance by virtue of having at least one Sickle Cell gene. Quote: Originally posted by Houngan If they are homozygous dominant, they don't have sickle cell.... As I said before, Sickle Cell Anaemia is a Recessive condition. However, if Sickle Cell Anaemia was a Dominant condition, you would have the disease even if you only had one gene (ie if you were heterozygous) for the Sickle Cell gene. And you would certainly have the disease if you had both genes (ie if you were homozygous) for Sickle Cell anaemia. Quote: Originally posted by Houngan If they are homozygous dominant, they ...... are susceptible to malaria. Again, Sickle Cell Anaemia is a Recessive not a Dominant condition but, if they were homozygous, they would actually have resistance to malaria not be susceptible to it as you have stated. Quote: Originally posted by Houngan The (formerly) lucky ones were heterozygous, and benefitted from being resistant to malaria without as crushing a burden from sickle-cell anemia. I have no problem with this.
	__________________ A secular society is one in which no one loses any liberty as a consequence of someone else's religious beliefs. NB Allowing yourself to get led around the nose by a person like Craig is a losing strategy. SH Morality is a social coating around a Darwinian core. JC My joke about freewill: There is no basis for it.

15th March 2003, 10:21 PM	#15
BillyJoe Penultimate Amazing Join Date: Aug 2001 Location: MOOROOLBARK Posts: 12,539	Quote: Originally posted by Houngan The sickle-cell gene isn't a total dominant gene. There are gradations whether homo or hetero. Many genes and gene complexes produce varied results in between homo dominant and homo recessive. You definitely seem to be confused between the meanings of heterozygous/homozygous and Recessive/Dominant. heterozygous: having only one gene for the condition. homozygous: having both genes for the condition. Recessive: need both genes to actually suffer from the condition. Dominant: need only one gene to actually suffer from the condition. therefore..... If you are heterozygous for a Recessive gene, you do not have the condition. If you are homozygous for a Recessive gene, you do have the condition If you are heterozygous for a Dominant gene, you have the condition. If you are homozygous for a Dominant gene, you have the condition.
	__________________ A secular society is one in which no one loses any liberty as a consequence of someone else's religious beliefs. NB Allowing yourself to get led around the nose by a person like Craig is a losing strategy. SH Morality is a social coating around a Darwinian core. JC My joke about freewill: There is no basis for it.

17th March 2003, 03:30 AM	#16
BillyJoe Penultimate Amazing Join Date: Aug 2001 Location: MOOROOLBARK Posts: 12,539	What do you say, Houngan? I mean I'm no expert. I think my summary is correct but I could be wrong and, if I am, I'd like to know so I don't make a fool of myself again.
	__________________ A secular society is one in which no one loses any liberty as a consequence of someone else's religious beliefs. NB Allowing yourself to get led around the nose by a person like Craig is a losing strategy. SH Morality is a social coating around a Darwinian core. JC My joke about freewill: There is no basis for it.

17th March 2003, 12:19 PM	#17
PygmyPlaidGiraffe Graduate Poster Join Date: Mar 2003 Location: Alberta, Canada Posts: 1,289	Quote: Originally posted by Houngan Folks, while I can't weigh in on whether this particular study is bogus, I have to point out that other such links do exist in the human body. In particular, there is a clear, proven link between black people, sickle-cell anemia, and malaria resistance. If someone is homozygous recessive with the sickle gene, they are extremely resistant to malaria, but unfortunately in deep trouble re: sickle cell anemia. If they are homozygous dominant, they don't have sickle cell, but are susceptible to malaria. The (formerly) lucky ones were heterozygous, and benefitted from being resistant to malaria without as crushing a burden from sickle-cell anemia. Genetics has no political correctness H. A female Anopheles gambiae mosquito feeding on a person could transmit the malaria parasite perhaps this link could help refresh people's memory about malaria: U.S. National Library of Medicine and U.S. National Institutes of Health provide info here: http://www.nlm.nih.gov/medlineplus/e...cle/000527.htm Quote: Sickle Cell Disease is much more common in certain ethnic groups affecting approximately one out of every 500 African Americans. Because people with sickle trait were more likely to survive malaria outbreaks in Africa than those with normal hemoglobin, it is believed that this genetically aberrant hemoglobin evolved as a protection against malaria. The CDC has info regarding malaria and history since the 16th century. http://www.cdc.gov/ncidod/eid/vol6no1/reiter.htm I would suggest that weather changes affect the range of the Anopheles. Where Anopheles goes the parisite goes and it can deliver the parisite to human popuations. Parishes in England kept records of deaths by ague (which, by detailed records of symptoms, parralels observed symptoms of malaria stricken people) over the centuries. A couple of Shakespeare's plays make reference to ague. Ague was associated with marshes/bogs which smell terrible (mal = bad , aria = air). I have not come across any evidence to suggest that the following train of thought is accurate , but I would imagine that the population in SW England over the centuries would produce individuals with sickle cell anemia. Bloodwork analysis would have been non-existant of course, and DNA tests of the individuals' remains would be needed to confirm how many people buried in parsihes at certain dates had Hb SS. I find it very interesting that males would take up residence in the marsh's bogs to make a living "quarrying" peat, a fuel. These men would come into town to find a spouse and sell their peat. More often than not the woman would succumb to ague, but not usually die before producing off-spring. The man would survive his wife, but in a man-of-the-marsh's life time he may have 2 or more wives (out-living 2 or more of them). The apparently resiliant man could father several children. I am aware the death rate for women was quite high due to many reasons, but quite often the woman would have several symptoms of ague. Note too that not every man that took up residence in marsh survived long enough to take a wife. The ague, which has a high possibility of being malaria, would be transfered by mosquitos. It has been verified by historical documentation and research that no less than 5 species of Anopheles were at one time or another present in Southwest England. As I stated I can not back it up, but the presence of Anopheles and the fact that Anopheles carry the pariste may have allowed the normally non-advantageous HbSS to become more common in indiviaduals with in the population of SW England, particularly among those that lived in the rural, marsh areas. HbSS, as undessirable as it may be to an organism, gives an organism an edge over like organisms that do not have HbSS. African Americans and "black" African populations today may have a higher proportion of individuals with HbSS, but I doubt that it has to do with a proven link between black people, sickle-cell anemia, and malaria resistance. I would suggest that the presense of Anopheles (which has a range limited due to enviromental and climatic factors which vary significantly over centuries) is more of an indicator as to whether a community has a higher incidence of malaria or HbSS. How to explain the incidence of HbSS in African Americans? Perhaps it has to do with how many generations affected individuals in a community are removed from their "homeland". Here is where my knowledge would prevent me from speculating how many generations would be needed to result in less individuals in a community from exhibiting HbSS. Of course, check out the evidence for yourselves, I am not an authority on Anopheles, HbSS, genetics, weather change, or parish burial records from SW England. Quote- "It's the correlation band wagon! Get on quick before it pulls away! I missed it back on the veldt and as a result I am (shamefully) correlationly challenged." - PPG, 2003

19th March 2003, 03:52 PM	#18
Houngan Scholar Join Date: Aug 2001 Posts: 116	Quote: Originally posted by BillyJoe What do you say, Houngan? I mean I'm no expert. I think my summary is correct but I could be wrong and, if I am, I'd like to know so I don't make a fool of myself again. Well, to put it bluntly, you are indeed wrong. You have a firm grasp of total dominance in genetics, but not of partial dominance. Some genes work one way, some work the other. In this case, folks who are hetero for the sickle gene do have a slight sickle-cell condition, and also malaria resistence. Homo recessive have a much more severe sickle, and homo dominant don't have sickle at all (and are malaria susceptible.) This is probably due to (and I in no way mean this as a slight) insufficient education. Schools like to present things as broad strokes in early classes, then get into the details later on. So, genetics is often introduced in the form of total dominant genes, so students can learn how to do Punnet squares. Later on, you get into partial dominance, and gene linking. (A good example of which is skin color. Obviously there are many gradations of darkness/melanin content in human skin, and as it turns out, it is dependent on several genes working together.) So, the short form is that although alleles are a binary system (dom., rec.), for some traits the 01 and 10 result are different than 11 and 00. H.
Houngan Scholar Join Date: Aug 2001 Posts: 116	__________________ Sum Ergo Cogito.

20th March 2003, 12:41 AM	#19
BillyJoe Penultimate Amazing Join Date: Aug 2001 Location: MOOROOLBARK Posts: 12,539	Houngan, Perhaps our disagreement is the result of us talking about different phenotypes? How does this sound?...... Dominant and Recessive refer to phenotype. If we are talking about the sickle cell phenotype, the inheritance is Dominant.... AA: normal cells AS: normal cells + sickle cells (so, actually, Codominant) SS: sickle cells. If we are talking about the sickle cell anaemia or the sickle cell disease phenotype, the inheritance is Recessive.... AA: no disease AS: no disease SS: disease. If I am way off beam, instead of a lengthy reply perhaps you have a reference.
	__________________ A secular society is one in which no one loses any liberty as a consequence of someone else's religious beliefs. NB Allowing yourself to get led around the nose by a person like Craig is a losing strategy. SH Morality is a social coating around a Darwinian core. JC My joke about freewill: There is no basis for it.

20th March 2003, 11:45 AM	#20
Houngan Scholar Join Date: Aug 2001 Posts: 116	Christ, Man! Why didn't you say so! I see exactly what you're saying now. I originally thought you didn't understand codominance at all. I'll take back everything I said; I was unaware that they were two different phenotypes. H.
Houngan Scholar Join Date: Aug 2001 Posts: 116	__________________ Sum Ergo Cogito.

21st March 2003, 01:53 AM	#21
BillyJoe Penultimate Amazing Join Date: Aug 2001 Location: MOOROOLBARK Posts: 12,539
	__________________ A secular society is one in which no one loses any liberty as a consequence of someone else's religious beliefs. NB Allowing yourself to get led around the nose by a person like Craig is a losing strategy. SH Morality is a social coating around a Darwinian core. JC My joke about freewill: There is no basis for it.