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Evolution/regarding genetic trait


Hi Dana,

My daughter is having exact teeth alignment as mine with the exact teeth misaligned as mine. I don't see any benefit of my misaligned teeth, in fact finding it ugly. Then why did this genetic trait transferred to my daughter and also why did I get misaligned teeth in the first place since neither of my parents, have misaligned teeth? Can evolution shed some light.

Dear Ameen,

In terms of evolution by means of natural selection, any trait can be considered:

adaptive - increases the survival and reproductive success of individual bearing the trait
maladaptive - decreases the survival and reproductive success of individual bearing the trait
neutral - does not affect the survival and reproductive success of individual bearing the trait

Unless dental misalignment severely interferes with an individual's ability to survive, acquire a mate, and reproduce, it will be passed on to the next generation.  So while you might consider the misalignment of the teeth to be unattractive, it evidently was not unattractive enough for you to successfully acquire a mate and reproduce!  :)  At worst, the trait is slightly maladaptive or neutral, but not enough to be taken completely out of the gene pool.

In addition, tooth alignment is affected by more than one gene.  When a trait is polygenic (controlled by more than one gene), it takes longer for natural selection to act on that trait, since different combinations of the "good" and "bad" genes affecting the trait can be inherited in different combinations in each individual.  As long as you don't inherit a fatal number of the "bad" versions of the genes, some of those "bad" versions will simply go along for the evolutionary ride and be inherited without doing the organism any real harm.

Evolution doesn't make perfect organisms.  It makes organisms that have traits that enable them to survive and reproduce as best they can in any given environment.

Hope that helps.



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Dana Krempels


I can answer questions about evolutionary mechanisms and theory, including genetic drift, mutation, natural selection, etc. I also can clear up misconceptions about evolution as it's sometimes talked about by those not well-versed in the subject (e.g., some politicians and many religious fundamentalists).


I have a Ph.D. in Biology, and presently teach Evolution and Biodiversity, Genetics, Botany, and Zoology at the University of Miami.

House Rabbit Society Beta Beta Beta Biological Honor Society

Exotic DVM Magazine (veterinary journal)

B.S. in Biology B.A. in English Ph.D. in Biology

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