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Name: Gerry A Adams
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a trait disappear for several generations and then reappear? Why?

Gerry, A general answer to your general question: YES!

This answer could be made more specific depending upon the trait you are thinking about. Since our genetic makeup consists of pairs of chromosomes, there is a possibility that a person could have 1 showing a particular trait, the other lacking the trait: given our current understanding of genetics we can predict whether the trait will be expressed. This would have to be answered--per trait-- as to whether the particular trait is dominant or recessive. Briefly, for a recessive trait to be expressed, it must occur in each of the pair of chromosomes. The recessive trait would be hidden by the dominant trait if either of the chromosomes possessed the dominant trait. Obviously if both chromosomes possess the dominant trait, THAT is what would be expressed.

You can picture how a recessive trait, hidden by a dominant- APPEARing individual, might be passed on through genetic material at conception. If both parents passed on the recessive trait, both of the offspring's chromosomes for that trait would be recessive, and the recessive trait would be expressed. This could occur in several combinations of either parent being Dd dD or dd, with the D being the dominant trait and the d being the recessive trait. Hope this helps!

Ric (rickru)

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