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Suggestions for single-gene dominant/recessive in humans?

  1. Dec 3, 2012 #1
    I am teaching a basic mathematics class, and am using Punnett squares as an example. In order to keep the students' interest, I am looking for examples of human traits, no Mendel's peas and so forth are not what I need. I wish to keep to monohybrids, as dihybrid hyprids would be too confusing for these students. I used widow's peak/ straight hair, but other examples I look at turn out not to be really the case: for example, eye color is determined by more than two genes, hair color can mix, lateral tongue rolling and attached ear lobes turn out also not to be as straightforward as the common myths have it, and so forth. Can someone give me some nicer, and valid, examples? Thanks.
  2. jcsd
  3. Dec 3, 2012 #2
    Ear lobes (attached, unatached), eye color (brown, pale - though the non brown colorations aren't so simple, but all are recessive to brown), Curling tongue.
  4. Dec 3, 2012 #3
  5. Dec 3, 2012 #4


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  6. Dec 3, 2012 #5
    Try any type of sex-linked disease. For example, males pass on a single Y chromosome to male offspring, and it is always penetrant.
  7. Dec 3, 2012 #6
    See Morgan's white eyed flies. Every generation of males will have some with white eyes because the mutation is sex linked, in this case it is on the X-chromosome. Flies are a little different than people, because their males are determined by having one X-chromosome, and females have two X-chromosomes, but this demonstrates the chromosomal theory of inheritance. Classic.
  8. Dec 3, 2012 #7
    Thanks for the excellent suggestions, Ygggdrasil and elegans. Very useful [although, unless my students have just watched "The Fly", they would show little interest in fly genetics. :-)]
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