A genetic question...

[Terminator2000]

Here's an odd question....

on many forums you see debates based on height....

One person brought an interesting approach to the whole height debate...and I'll share that with you gents, in just a minute, but first..

Here's a scenario..

A really tall guy, say 6'3 dates a shorter girl say 5'5...and they hit it off, date for a couple months, year or 2 and then finally get married. Further down the line they have kids. Now, keeping in mind the heights of the two parents, say they have a girl, a daughter...and she grows up and gets her father's height. 6'3 and then further down the line, they have another kid. A boy and he grows up and gets the mother's height. 5'5.

and so and and so forth.

The question I have. As its a long shot if there's any qualified people to answer this question.

The guy that argued towards height in the forum. His argument was, that Height is Random. My argument is the same, but I go a step further and say it doesn't discriminate based on gender.

So, if a father is really tall and the mother is average height or shorter. Then the heights of the parents can be random when they have children.

This is what the other guy in the forum argues. (He's 5'5 btw)

"I think it doesnt matter where ur from..its just ur genetic mix...Im taller then my dad, and my brother will most likely be taller then me

to think thats its because of race is rediculous..my granny is like...4'11 Lol..and 1 of my uncles is 6'2..

so again..race has nothing to with it."

and then he says...


"then explain to me why my uncle majid is 6'2....he looks like my granny..n looks like my grandpa..but hes tall..

genetics are random as $#@* .
.
.n how much milk n food the kid eats during their youth..

thats why in the dark ages of Europe..the average height of a man was not 5'9..

but i could be wrong"

He even takes it further by saying...

"lol im not saying they arent..Im sure 2 tall europeans have had a kid that isnt tall or as tall as them/"

That two tall parents can possibly have a short kid.



His argument is...that Height is Random.

Meaning the parents can be any height, and the kid can be any height, according to the genes of the family tree (eg. uncles, cousins, aunts...)

My argument is...that Height doesn't discriminate based on Gender.

and I have seen evidence of this, in some people I met. Like a daughter acquired her father's height, while her mom is shorter.

My question is...

Is the genes for tall height a dominant gene and the gene for short height a recessive gene?

 

[LordLoki]

The answer is about 3 text books long. So I do not know how you can get the real answer on a chat board.

Over simplifying greatly:

There are several genes impacting on height. Not one. Each gene can be dominant or recessive. A dominant gene trumps a recessive gene. An individual gets one gene from the mother, the other from the father. When each pair is formed they create a pair. A pair can be Dominant-dominant, Dominant-recessive, or recessive-recessive. Just to make it more complicated some gene pairs are not defined as Dominant/ recessive.

So how does it work? Well when the sperm and egg is formed you get a random distribution of the father’s / mother’s gene codes. Which sperm meets which egg is also a random act. That is why there is a wide variation of looks in the same family.

At the moment of conception the genetics define the maximum height that individual can grow to. One of those genetic codes is linked to the sex of the individual. The genetic XY code for men will result in a taller person than the genetic code that creates a woman.

So…

1) maximum height is set by genes inherited from parents

2) maximum height programmed in genes is impacted by sex genes. Males with same code are taller than females with same code.

3) maximum height is controlled by health and nutrition of mother during pregnancy. Some claim by her health and nutrition during her entire life. Embryos are very sensitive.

4) maximum height is controlled by health, nutrition, and exercise from birth to adult hood.

There are also mutations and rather odd genetic exceptions that can create abnormally tall or short people.


Does that answer your question?

 

[Sasha Jones]

............ A dominant gene trumps a recessive gene. An individual gets one gene from the mother, the other from the father. When each pair is formed they create a pair. A pair can be Dominant-dominant, Dominant-recessive, or recessive-recessive. ..................

Ok so if what I have been told is true, that Brown eyes are dominant, how did BOTH of my children end up with Blue eyes when I have Brown eyes and my hubby has Hazel ones?

Ok so it isn't height related, but it is gene related which is sort of on the same topic

 

[MissCroft]

Ok so if what I have been told is true, that Brown eyes are dominant, how did BOTH of my children end up with Blue eyes when I have Brown eyes and my hubby has Hazel ones?

That often happens. It has to be because you have a blue-eyed gene and a brown-eyed gene and so does your hubby (well, hazel but it's the same -it's also dominant). In both of your cases, the brown-eyed gene 'won out' because it was dominant. However, when the two of you had children, they both inherited a blue-eyed gene from each of you. (Because the blue-eyed gene is recessive, you need one from each parent).

With you and your hubby, there are four possible combinations: BB, Bb, bB, and bb. The first three combos would produce brown eyes and the bb would be the blue-eyed recessive outcome. So there is a 25% chance that the two of you will produce blue-eyed offspring. In your case, that 25% chance occured with both of your children. Hope this helps!


The height gene is a little more complicated...

 

[Samurai Joey]

Hi Sasha,

It is important to keep in mind in that even though brown eyes are dominant, you and your husband may still carry the blue-eyed recessive gene, since you inherit copies of genes from both your father and your mother. In genetics this is the difference between your phenotype (i.e. what is physically evident) and your genotype (i.e. what is actually encoded in your gene).

According to a simplistic Punnett (sic) diagram it works like this:


Father: brown eye-blue eye gene (has hazel or brown eye)
Mother: brown eye-blue eye gene (has brown eye)
Children: 75% brown eye, 25% blue eye

So your kids each inherited the recessive blue eye trait from both you and your husband!

To further complicate things, there is an additional gene which activates certain fat deposits around the iris, which gives one's eye colour a greenish tinge, which is how you can also get green or hazel eyes.

I hope this sort of answers your questions.

Thanks,

Samurai Joey

 

[LordLoki]

About the height - it essentially follows statistical distribution within the population group, regardless of the height of parents.

Well sort of. the "population group" is actually the gene pool the individuals genes can come from. Not the population at large.

Being "VERY TALL" is not a single gene, it is several genes all rolling "7"s. The reason it is noot a simple Cross, is that some Tall gene pairs are dominant, but in other pairs the Short gene is dominant. Hence the normal distribution created by a finite series of gene pairs.

Translation: your parents give you the genes that set your maximum height. Also works for strength, etc

 

[Never Compromised]

there are four possible combinations: BB, Bb, bB, and bb..

What Miss Croft is saying, is that if you book with her while this thread is active, not only will you receive a BB, but as a special bonus a Bb. And if you act right now, you are also in for a bb.

 

[red]

You guys did an excellent job on explaining the eye color. There is one little thing that should be mentioned: Blue-eyed parents can have only blue-eyed kids. So, if you see a blue-eyed couple and their kids have brown (or any other non-blue) eyes, then you will know that something suspicious happened there.

About the height - it essentially follows statistical distribution within the population group, regardless of the height of parents. (BTW, that's where Darwin was wrong. He assumed that, for example, tall giraffes' offspring will be also taller than average and that's how they eventually ended up with the long necks. Evolution is actually driven by successful mutations. There are lots of good books written on that topic, by my favorite is Erwin Schroedinger's "What's life", one of the most beautiful scientific books ever written in layman's words, by one of the greatest physicists of all time.)

Although not common, two blue-eyed parents can produce children with brown eyes," says Richard A. Sturm, a Principal Research Fellow at the Institute for Molecular Bioscience at the University of Queensland in Brisbane, Australia.




Eye color is a complex trait that depends on the state of several interacting genes. The gene that usually decides the issue (blue eyes or brown eyes) is the OCA2 gene on chromosome 15. But it comes in different strengths. A person with a weak form of the OCA2 gene will have blue eyes. Likewise a person with a strong form will have brown eyes.

The plot thickens, though, because an individual also has other eye-color genes that each has a say in the final eye-color outcome. For example, if one of these lesser genes is strong, it can make the weak form (blue) of OCA2 work much more effectively — almost like the strong form (brown). Then the eye color may be a light brown or muddy grey. In fact, the resulting color can be any shade of brown, hazel/green, or blue depending on the strengths of the interactions.

Yes, Frederick. Two brown-eyed parents can have a blue-eyed child. In fact, this is fairly common.


http://www.usatoday.com/tech/columnist/aprilholladay/2004-10-14-wonderquest_x.htm
http://www.thetech.org/genetics/ask.php?id=2