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Why am I short?

  1. Sep 12, 2005 #1
    I'm not very knowledged in genetics, although i'm interested in the subject, and was hoping someone could give me some insight into any possible reasons for why i'm short.

    I'm a caucasian male and i'm only around 5'7". I know I take after my father who is also around my height, but I don't understand who he took after. My grandfather (on his side) was around 6'1" - 6'2", on a side note my grandfather on my mothers side is also around 6'1", could my father have taken after his mother? But if so then his mother was, like most women, shorter than 5'7".

    I'm just curious and thought since i'm passing through i'd ask :tongue2:
     
  2. jcsd
  3. Sep 12, 2005 #2

    Evo

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    Genes are only partly responsible for things like height. Nutrition & health, for example, will affect height.
     
  4. Sep 12, 2005 #3

    selfAdjoint

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    I think that height is the result of interaction of several genes, not to mention nutrition.

    That said, a little guesswork...

    It's important to know that at every gene site in your genome you have TWO alleles (gene varieties), one from your mother and one from your father. Now as your father was short in a family of taller men, it looks like he inherited "short" alleles at some height related site from both sides - "short" would be recessive and only show up in the body if there were no "tall" allele with it. So your father would have had two "shorts" and passed one of them on to you. You would then have gotten another "short" from your mother. Since she was normal height, she would have had a "tall" allele paired with her short, but by the luck of the draw, you got the "short".

    Because of the recessive character, your senior relatives could carry "short" alleles without expressing them, since they would have been paired with "tall" alleles.
     
  5. Sep 12, 2005 #4
    It also might help to reveal your age...
     
  6. Sep 12, 2005 #5
    Thank you for your reply selfAdjoint. So that means my grandfather (on his side) would have to of had one short allele and one tall allele, correct? Very good response, it has helped alot, thanks. I've looked at places like giantscientific.com, but I don't know if their natural growth excercise techniques will be worth the time and effort considering i don't know if they will be effective.

    Artermis - I'm 20 and well past my growth stages. Some people do grow up to the age of 25, but I don't think i'll be one of them.
     
  7. Sep 12, 2005 #6

    Moonbear

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    A lot of factors can affect your final height. In addition to genetics and nutrition, which were already mentioned, age of puberty (which may also be genetic) and the levels of growth hormones and other hormones during puberty can affect height (boys who go through puberty younger tend to be shorter than boys who go through puberty when older; this is due to the epiphyseal plates in your bones...the parts that let the long bones continue growing in childhood..."close" during puberty under the influence of androgens and growth hormones...maybe some other more recently discovered hormones too...once that happens, no more growth in height will occur).
     
  8. Sep 13, 2005 #7
    Some research has shown that if either of your parents had their height development restricted by diet, it is a trait that can be passed to you (quite a violation of inheritence).

    I'm sure I read it in Newscientist..
     
  9. Sep 13, 2005 #8

    DaveC426913

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    I am 41 and I choose to believe that 5'7" is not "short".

    I would bet that you are suffering from
    a] media stereotyping more than any real deficit in height. It is the same as a "normal"-sized woman asking why she is so fat (because she weighs more than 98lb Lara Flynn Boyle)
    combined with
    b] hypersensitivity to your height. It may appear to you that most men are taller than you, but that's a self-fulfilling prophecy. You notice them.
     
  10. Sep 13, 2005 #9

    selfAdjoint

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    Right. In this (perhaps oversimplified) simple Mendelian picture, the paternal grandfather, being tall but passing on a short allele would have had to have a mixed pair. You don't say what your paternal grandmother was, but as long as she also carried a mixed pair she could (with 50% probability) pass on a short allele to your father.
     
  11. Sep 13, 2005 #10
    Forgive me if I'm getting this wrong, it's been a number of years since my genetic coursework.

    I don't think there's one tall allele and one short allele. I think there's dozens of them, and they're cumulative. So if you break the bank and get 40 tall alleles, you'll be extremely tall; luck out and get 40 alleles and you're Gary Coleman; get 20 tall and 20 short and you'll be average.

    At least I think that's how it works. I forget the name of that sort of trait.
     
  12. Sep 13, 2005 #11

    Moonbear

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    You're right. SelfAdjoint mentioned it earlier, but that might have gotten missed. His example was to explain what alleles are, not to say it was just one responsible.
     
  13. Sep 13, 2005 #12
    And yes, you need to look at the females in your family history. What causes a gene to be dominate is not understood in regards to height. Like red hair, height differences can skip generations.
    In my family I have a sister who is over 6ft tall{same as my great grandmother} while I am 5'6" the same height as my mother.
     
  14. Sep 26, 2005 #13
    guys this kind of question is what NCBI is for.
     
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