[neilep (OP)]

Dearest Scholastic Academics of Sagacious Brain Activity,

Why do we have different colured hair and eyes ?...


We're all black, white, amber ? (sorry ..for some reason I feel awkward saying yellow)...and various other tints...

but why the colour differences of hair ?....and why even more so in variety of eye colour ?

I realise there are specific hereditary reasons why we have different colours but I'm interested in the fundamental principle of why we have different colours of hair and eye anyway.

Thank you and Happy sunday...Phew it's hot eh ?



Men are the same as women, just inside out !

[ukmicky]

Its all to do with the Melanin pigment in your eyes, the same stuff which causes the skin of  black people to be brown and the skin of white people to be er brown[].

Its is all controlled by our genes.

Melanin is the bodies way to naturaly protect us from the sun and is the reason why we tan.  

The article below explains it a bit better. []
http://www.seps.org/cvoracle/faq/eyecolor.html [Links inactive - To make links active and clickable, login or click here to register]
Michael

[another_someone]

This is a racial issue.

Many years ago I was working with a Sri Lankan, and he was totally bemused about why his passport carried information about colour of hair, colour of eyes, etc; since outside of Europe (and excluding populations of European descent), everyone has brown hair and brown eyes.

Why are Europeans different?  Why do other animals come is all sorts of colours – aside from camouflage (unlikely in this case), it is usually a matter of sexual attraction (blue eyed blondes have always been regarded, at least blonde women, as sexually desirable, and that alone would improve the likelihood of blue eyed blondes being born in the next generation).

George

[Karen W.]

Aren't we touching upon a bit of Hitlers theory to cultivate the perfect race! Yuck!

  George I am not disagreeing with you. What you said just brought thoughts of what Hitler was doing into my mind, sorry for the distasteful thoughts! They were not really on topic!

  I say Michael's right its the "Genes." I think certain chromosomes help determine genetic eye and hair color don't they?

[neilep (OP)]

THANK YOU Michael and THANK YOU George....(and special thanks to luverly wuverly squishy Karen...xxxxxxx) []

I can certainly understand the genetics behind it...

...it's the reason why different coloured eyes exist in the first place that I'm interested in !

From what you're saying George Geography has a lot to do with it ...or would it be climate ?...could there be a climatic reason behind the colour of eyes ?...which if so...then that would indicate that eyes differ in the way they deal with light determined by the environment.

 I understand that we all see slightly different from each other but does a blue eyed person have an ocular advantage over a brown eyed person under certain circumstances ?...and the other way round of course !

Outside of Europe (and European descent)..I wonder if there are cases of brown hair and blue eyes !...perhaps only with some European input !!..if you know what I mean..nudge nudge wink wink !!

There must be an essential factor why different coloured eyes exist in the first place.



Men are the same as women, just inside out !

[ukmicky]

Europeans are different because in general the sun is not so strong here and so require less natural protection from the sun.

Eye wise the darker the eyes the more Melanin pigment their is and so the more of the nasty suns rays are absorbed and turned into heat.

Also the dark eyed gene's are more dominate than blue eyed genes, in most cases.


Menalin is also the best skin protection from the sun know to man  and it also activly fights against free radicals, 90 percent of skin cancers are in fair skinned people.
Michael

[Karen W.]

Hummm! Interesting point. Now I know what you mean! I think I misunderstood the question the first time round.
   I wonder if there is a better tolerance to light in any given eye color? That is an interesting question. Perhaps the amount of light does have an effect on eye and hair color....Karen  P. S. It is overcast and bleak here today, but a lovely morning anyway!

[another_someone]

Firstly, i don't know about eye colour, but in terms of hair colour, many people from Western Ireland (I think this probably covers much of the extreme western edge of Europe) have very fair skin but dark hair, so there is not necessarily a direct correlation between eye/hair colour and skin colour (although most commonly light skin goes with light hair – don't know about eyes).

As far as I am aware, the genes controlling eye colour have nothing to do with the genes controlling skin colour.

There are a couple of issues regarding skin colour.

Firstly, a light skin would normally indicate a fairly sheltered lifestyle, and (particularly for a woman) it would imply a person of some wealth, who could afford not to have to work out in the sun.

With regard to blue eyes, blue eye colour is recessive, so if it once was associated with some past royalty or nobility, then having blue eyes implied a high probability of thoroughbred inheritance (i.e. both your parents must have inherited this unusual gene).  Furthermore, blue eyes are associated with newborn babies, and so maybe there is some similar emotional link regarding blue eyed adults.

One story I have heard, although I do not know how true it is, that the notion of 'blue blooded royalty' comes from the days that the Visigoths (who were a light skinned Germanic tribe) ruled Spain, and it reflected the light (slightly bluish) skin of the ruling class of the darker skin natives.

George

[Carol-A]

Melanin protects us, to some degree from the damaging effects of the sun, and so people livingclose to the equator will have dark skin and eyes, to prevent too much uv damage. The downside of a lot of melanin is that it reduces the amount of vitamin d you can make. Near to the equator, where sun is not a problem, vitamin d is not a problem, but closer to the poles, where sun is limited, a dark skin could result in ricketts, so closer to the poles, there has been an advantage to reducing the level of melanin. Melanin is what causes hair and eye colour too. Skin and hair pigment is made up of different types of melanin.  There are two broad groups of melanin, eumelanin, which is brown, and phaeomelanin, which is red. If you have high levels of melanin, the hair and eyes will basically look black, but as the total level of melanin falls, differences in hair and eye colour will show. It is not fully understood why there are some people with very dark hair but fair skin, but people are working on it!

[neilep (OP)]

THANK YOU George and THANK YOU Carol-A (welcome to the site )

This is all very interesting....I am one of those very fair skinned people with dark hair and blue eyes, I only have to be in the sun for a few minutes before turning pink !!...my daughter...even more so. She is so pale she is ashen and has a face full of freckles like I did when I was her age.........I actually love her complexion and we all have to use the strongest SPF when buying sun cream.

I do find the nature of eye colouration particularly interesting and so thank you for your fascinating comments.


Men are the same as women, just inside out !

[another_someone]

quote:Originally posted by Carol-A

Melanin protects us, to some degree from the damaging effects of the sun, and so people livingclose to the equator will have dark skin and eyes, to prevent too much uv damage. The downside of a lot of melanin is that it reduces the amount of vitamin d you can make. Near to the equator, where sun is not a problem, vitamin d is not a problem, but closer to the poles, where sun is limited, a dark skin could result in ricketts, so closer to the poles, there has been an advantage to reducing the level of melanin. Melanin is what causes hair and eye colour too. Skin and hair pigment is made up of different types of melanin.  There are two broad groups of melanin, eumelanin, which is brown, and phaeomelanin, which is red. If you have high levels of melanin, the hair and eyes will basically look black, but as the total level of melanin falls, differences in hair and eye colour will show. It is not fully understood why there are some people with very dark hair but fair skin, but people are working on it!

I have heard that even more of a problem that vitamin D is folic acid (which can also be obtained from sunlight).

George

[ukmicky]

Its all to do with the Melanin pigment in your eyes, the same stuff which causes the skin of  black people to be brown and the skin of white people to be er brown[].

Its is all controlled by our genes.

Melanin is the bodies way to naturaly protect us from the sun and is the reason why we tan.  

The article below explains it a bit better. []
http://www.seps.org/cvoracle/faq/eyecolor.html [Links inactive - To make links active and clickable, login or click here to register]
Michael

[another_someone]

This is a racial issue.

Many years ago I was working with a Sri Lankan, and he was totally bemused about why his passport carried information about colour of hair, colour of eyes, etc; since outside of Europe (and excluding populations of European descent), everyone has brown hair and brown eyes.

Why are Europeans different?  Why do other animals come is all sorts of colours – aside from camouflage (unlikely in this case), it is usually a matter of sexual attraction (blue eyed blondes have always been regarded, at least blonde women, as sexually desirable, and that alone would improve the likelihood of blue eyed blondes being born in the next generation).

George

[Karen W.]

Aren't we touching upon a bit of Hitlers theory to cultivate the perfect race! Yuck!

  George I am not disagreeing with you. What you said just brought thoughts of what Hitler was doing into my mind, sorry for the distasteful thoughts! They were not really on topic!

  I say Michael's right its the "Genes." I think certain chromosomes help determine genetic eye and hair color don't they?

[neilep (OP)]

THANK YOU Michael and THANK YOU George....(and special thanks to luverly wuverly squishy Karen...xxxxxxx) []

I can certainly understand the genetics behind it...

...it's the reason why different coloured eyes exist in the first place that I'm interested in !

From what you're saying George Geography has a lot to do with it ...or would it be climate ?...could there be a climatic reason behind the colour of eyes ?...which if so...then that would indicate that eyes differ in the way they deal with light determined by the environment.

 I understand that we all see slightly different from each other but does a blue eyed person have an ocular advantage over a brown eyed person under certain circumstances ?...and the other way round of course !

Outside of Europe (and European descent)..I wonder if there are cases of brown hair and blue eyes !...perhaps only with some European input !!..if you know what I mean..nudge nudge wink wink !!

There must be an essential factor why different coloured eyes exist in the first place.



Men are the same as women, just inside out !

[ukmicky]

Europeans are different because in general the sun is not so strong here and so require less natural protection from the sun.

Eye wise the darker the eyes the more Melanin pigment their is and so the more of the nasty suns rays are absorbed and turned into heat.

Also the dark eyed gene's are more dominate than blue eyed genes, in most cases.


Menalin is also the best skin protection from the sun know to man  and it also activly fights against free radicals, 90 percent of skin cancers are in fair skinned people.
Michael

[Karen W.]

Hummm! Interesting point. Now I know what you mean! I think I misunderstood the question the first time round.
   I wonder if there is a better tolerance to light in any given eye color? That is an interesting question. Perhaps the amount of light does have an effect on eye and hair color....Karen  P. S. It is overcast and bleak here today, but a lovely morning anyway!

[another_someone]

Firstly, i don't know about eye colour, but in terms of hair colour, many people from Western Ireland (I think this probably covers much of the extreme western edge of Europe) have very fair skin but dark hair, so there is not necessarily a direct correlation between eye/hair colour and skin colour (although most commonly light skin goes with light hair – don't know about eyes).

As far as I am aware, the genes controlling eye colour have nothing to do with the genes controlling skin colour.

There are a couple of issues regarding skin colour.

Firstly, a light skin would normally indicate a fairly sheltered lifestyle, and (particularly for a woman) it would imply a person of some wealth, who could afford not to have to work out in the sun.

With regard to blue eyes, blue eye colour is recessive, so if it once was associated with some past royalty or nobility, then having blue eyes implied a high probability of thoroughbred inheritance (i.e. both your parents must have inherited this unusual gene).  Furthermore, blue eyes are associated with newborn babies, and so maybe there is some similar emotional link regarding blue eyed adults.

One story I have heard, although I do not know how true it is, that the notion of 'blue blooded royalty' comes from the days that the Visigoths (who were a light skinned Germanic tribe) ruled Spain, and it reflected the light (slightly bluish) skin of the ruling class of the darker skin natives.

George

[Carol-A]

Melanin protects us, to some degree from the damaging effects of the sun, and so people livingclose to the equator will have dark skin and eyes, to prevent too much uv damage. The downside of a lot of melanin is that it reduces the amount of vitamin d you can make. Near to the equator, where sun is not a problem, vitamin d is not a problem, but closer to the poles, where sun is limited, a dark skin could result in ricketts, so closer to the poles, there has been an advantage to reducing the level of melanin. Melanin is what causes hair and eye colour too. Skin and hair pigment is made up of different types of melanin.  There are two broad groups of melanin, eumelanin, which is brown, and phaeomelanin, which is red. If you have high levels of melanin, the hair and eyes will basically look black, but as the total level of melanin falls, differences in hair and eye colour will show. It is not fully understood why there are some people with very dark hair but fair skin, but people are working on it!

[neilep (OP)]

THANK YOU George and THANK YOU Carol-A (welcome to the site )

This is all very interesting....I am one of those very fair skinned people with dark hair and blue eyes, I only have to be in the sun for a few minutes before turning pink !!...my daughter...even more so. She is so pale she is ashen and has a face full of freckles like I did when I was her age.........I actually love her complexion and we all have to use the strongest SPF when buying sun cream.

I do find the nature of eye colouration particularly interesting and so thank you for your fascinating comments.


Men are the same as women, just inside out !

[another_someone]

quote:Originally posted by Carol-A

Melanin protects us, to some degree from the damaging effects of the sun, and so people livingclose to the equator will have dark skin and eyes, to prevent too much uv damage. The downside of a lot of melanin is that it reduces the amount of vitamin d you can make. Near to the equator, where sun is not a problem, vitamin d is not a problem, but closer to the poles, where sun is limited, a dark skin could result in ricketts, so closer to the poles, there has been an advantage to reducing the level of melanin. Melanin is what causes hair and eye colour too. Skin and hair pigment is made up of different types of melanin.  There are two broad groups of melanin, eumelanin, which is brown, and phaeomelanin, which is red. If you have high levels of melanin, the hair and eyes will basically look black, but as the total level of melanin falls, differences in hair and eye colour will show. It is not fully understood why there are some people with very dark hair but fair skin, but people are working on it!

I have heard that even more of a problem that vitamin D is folic acid (which can also be obtained from sunlight).

George

[another_someone]

quote:Originally posted by neilep
This is all very interesting....I am one of those very fair skinned people with dark hair and blue eyes, I only have to be in the sun for a few minutes before turning pink !!.

So, do you have any Celtic or Basque blood in you?

quote:Originally posted by neilep
This is all very interesting....I am one of those very fair skinned people with dark hair and blue eyes, I only have to be in the sun for a few minutes before turning pink !!.

So, do you have any Celtic or Basque blood in you?

Not that this is proof of anything, since various groups have mixed a great deal, but it is supposedly more prominent that pale skin dark hair exists in these groups.

http://www.megalithic.co.uk/print.php?sid=2146411686 [Links inactive - To make links active and clickable, login or click here to register]

quote:
THE Rh-NEGATIVE POPULATION
The first mesolithic people from the Basque peninsula were without doubt the most experienced sailors of the Atlantic. These people who populated the northwest coast of Europe have a very special blood peculiarty which thier descendants are still living today. Dr.Luigi Cavalli-Sforza published a map of the populations with the highest percentage of thier members with Rh-negative blood. He wrote:


"Rh-negative genes are frequent in Europe, infrequent in Africa and West Asia, and virtually absent in East Asia and among the aboriginal populations of America and Australia. One can estimate degrees of relatedness by subtracting the percentage of Rh-negative individuals among, say, the English (16%) from that of the Basques (25%) to find a difference of nine percentage points.

The highest percentage of people with rh- blood is found in the Atlas mountains of Morocco(40%). The next highest are the Basques, reported in different publications as having 25 and 32%, depending on location. The people of northwest Ireland, the Highland Scots and the western islanders of Norway all have between 16 and 25%, while the Lapps of Norway and Finland have between 5 and 7%

George

[neilep (OP)]

I'm no too sure actually George...my blood is Rh+ and my ancestery heralds from poland and Russia...so what does that make me......Slavic ?....I don't know !

Men are the same as women, just inside out !

[another_someone]

Most recently, that area would be considered Slavic, although historically it has been populated by Balts, and before that by Finns.  You do not sound like a Finnish phenotype, and since Balts and Slavs are both Indoeuropean, it could be either of those.

George

[another_someone]

Can't say how accurate the following is, but it is an interesting and relevant comment:

http://www.futurepundit.com/archives/cat_human_population_genetics.html [Links inactive - To make links active and clickable, login or click here to register]

quote:
2002 October 10 Thursday
Mutation for redheads is of recent origin
In evolutionary terms a mutation that arose only 20,000 years ago is pretty recent. If this is correct then the pheomelanin variation of melanin that produces red hair is pretty new.

quote:According to the most recent estimates, the first red hair sprouted just 20,000 years ago, long after the advent of modern homo sapiens.

George

[gecko]

"Melanin protects us, to some degree from the damaging effects of the sun, and so people livingclose to the equator will have dark skin and eyes, to prevent too much uv damage. The downside of a lot of melanin is that it reduces the amount of vitamin d you can make. Near to the equator, where sun is not a problem, vitamin d is not a problem, but closer to the poles, where sun is limited, a dark skin could result in ricketts, so closer to the poles, there has been an advantage to reducing the level of melanin."

if this is true, why arent dark haired and dark eyed people dying from vitamin D depletion all through russia and northern europe? is it because nutrition is more adequate?

id say that also, why arent fair haired and fair eyed people dying from UV exposure closer to the equator, but its seems as though they are, unfortunately...

also, this lumping of races into their phenotype doesnt always hold water. i guess its a good general guide, but im afraid not all(and not most) caucasion babies are born with blue eyes, as many of these simplified views of inheritance assume.

[another_someone]

quote:Originally posted by gecko
if this is true, why arent dark haired and dark eyed people dying from vitamin D depletion all through russia and northern europe? is it because nutrition is more adequate?

Rickets (caused by vitamin D deficiency) was commonplace even amongst Caucasians in Northern Europe, but since that time it has been combated by dietary supplements.

http://www.beyonddiscovery.org/content/view.txt.asp?a=414 [Links inactive - To make links active and clickable, login or click here to register]

quote:
Rickets was a common disease afflicting children in the eighteenth century. However, the cause for it was not well understood, and many children died because there was no cure (see Tracing the Cause of Disease). As physicians began investigating other diseases such as beriberi, they realized that there were factors in food other than proteins and salts which were essential to health. Research into these “accessory food factors” led scientists to demonstrate the existence of vitamins (see "…a substance different from protein and salts..."). As scientists turned their attention to rickets again, they found that exposure to sunlight seemed to be an effective treatment. Physicians also were attempting to isolate nutrients in food that might help and found that an unknown nutrient in cod liver oil was effective against rickets. Following the designation of vitamins in alphabetic order, they dubbed this new nutrient vitamin D.

One of the reasons vitamin D was a puzzle to scientists for so many years was that it was initially misidentified as a true vitamin, that is an essential substance that our bodies cannot manufacture and which therefore, can only be obtained from our food. But, unlike essential dietary trace elements, such as vitamins A, B, and C, which humans must get directly from food, vitamin D can be produced in the body through a photosynthetic reaction when the skin is exposed to sunlight. The resulting substance is only a precursor, however, which must then undergo two transformations--first in the liver and then in the kidney--to become the biologically active substance the body uses. This active form of vitamin D is a hormone, chemically akin to familiar steroid hormones, such as the sex regulators testosterone and estrogen and the stress regulator cortisol.

Independently, the two teams of researchers irradiated excised skin as well as such food substances as vegetable oils, egg yolk, milk, lettuce, or rat chow and found that irradiation produced a substance that seemed to work on rickets much as the vitamin D in cod-liver oil did. Rats that were fed irradiated foods or irradiated skin were protected against rickets, whereas those fed unirradiated foods or skin were not. Recognizing that simply irradiating certain foods that were common in most people's diets could spare large numbers of children from the bone disease, Steenbock patented the food irradiation process using ultraviolet light in 1924, donating all future proceeds to support research at the University of Wisconsin.

Because of these discoveries, it became possible to synthesize the vitamin in large quantities. Synthesizing the vitamin costs a fraction of what it costs to irradiate foods and does not destroy or change food flavors, as irradiation sometimes does. Synthesized vitamin D provided the capstone of the public health campaign to eradicate rickets. For his "research into the constitution of the sterols and their connection with the vitamins," Windaus was awarded the Nobel Prize for Chemistry in 1928.

http://www.amren.com/mtnews/archives/2006/07/us_calls_for_fo.php [Links inactive - To make links active and clickable, login or click here to register]

quote:
Folic acid addition to food is of greatest benefit to light-skinned children. Women of all races strike a very fine balance between being too fair for their environment and being too dark. Fair skin allows in enough sunlight to permit Vitamin D production even in areas that are usually overcast, like northern Europe or northeast Asia. Skin that is too dark won’t permit this, so milk is fortified with Vitamin D. Dark skin on the other hand does not appear to have evolved as protection against skin cancer; it takes several decades to develop skin cancer, by which time someone will already have produced offspring, so evolution is essentially done with them. The dark skin is to prevent the UV in sunlight from breaking down folic acid in pregnant women. A folate shortage during pregnancy results in a baby with spina bifida.

http://www.berkeleywellness.com/html/ds/dsFolicAcid.php [Links inactive - To make links active and clickable, login or click here to register]

quote:
Another complicating factor for folate may be sunlight. A recent article in Scientific American cited evidence that ultra-violet radiation can actually penetrate the skin and destroy folate in the bloodstream, especially in fair-skinned people. This is another reason to avoid sunbathing.

George

[gecko]

good finds!

i think the answer has been found.