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Dominance but not majority? Why?!

Genetics as it applies to evolution, molecular biology, and medical aspects.

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Dominance but not majority? Why?!

Postby goddessxx » Mon Jan 30, 2006 4:29 am

This is a discussion question. I've been searching online for a while but couldn't find a satisfactory answer.

Heredity: Dominant and Recessive

Why does dominant genes does not necesarily mean that it will affect the majority of the population?

For example, having more than 10 fingers is dominant, but most people are in the recessive category, which is just 10 fingers. If that's how the traits are, wouldn't the recessive become dominant?

Thank you for all your help :D
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Postby bearhug » Mon Jan 30, 2006 12:12 pm

Recessive is always recessive. Having 10 fingers is the wild type. If everyone is homozygous recessive for this trait than it is impossible for there to be a dominant allele, unless there's a mutation.
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Postby MrMistery » Mon Jan 30, 2006 7:49 pm

Well, i am not sure about this example. What you are saying is that a man with polidactilia will always have children with more than 10 fingers? Seems strange.

About the frequence of an allele, have a look at hardy-weinberg. There is no direct relation between the dominance and it's transmition
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Postby bearhug » Tue Jan 31, 2006 3:51 am

I think you misunderstood me.
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Postby MrMistery » Tue Jan 31, 2006 7:17 pm

I take it back. If a man has more than ten fingers he may be FF or Ff. So some of his children will have more than 10 fingers. Right?
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Postby M.Shanti Priya » Thu Feb 02, 2006 9:52 am

Even though polydactyly is controlled by a dominant allele it is accompanied by incomplete penetrance hence not observed in majority of the population. The gene doesnot penetrate or show the phenotype associated with the genotype in all the individuals with that genotype.
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