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Tasy
Lv 4
Tasy asked in Science & MathematicsBiology · 1 decade ago

Genetics - Pedigree line - recessive.?

How can two parents with a recessive gene (aa) not affect the child?

Wouldn't the child have the recessive phenotype too.

Update:

the parents both have the disease

1 Answer

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  • 1 decade ago
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    If you cross aa x aa the offspring must have the recessive "a"phenotype. If you cross aa x Aa though, the offspring will be 50% "A" phenotype and 50% "a" phenotype.

    So yes, if both parents have the disease and it is recessive, all the offspring must have the disease as well.

    Since you are asking this, I'm going to assume that's not what the pedigree shows. Does the question explicitly state the trait is recessive? Sometimes they don't tell you and you need to determine that yourself. Hope this helps.

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