genes and how we get them?

Question

10. A couple has a silver-eyed child. Both parents have purple eyes.

(a) Based on the information provided above, is the trait “silver eyes” dominant or recessive?

Answer: _______________________ (1)



Why/How do we know “silver eyes” are a dominant or recessive trait? (include an explanation of the parents genotype and how/why we know this!) (2)









(b) Using a punnett square, show how a mating of two purple-eyed people could produce a silver-eyed child. Remember to use the letter “E” as your allele. (1)

Answer 1

1. Silver has to be recessive.
2. We know silver is recessive because neither parent showed this trait, but the offspring could get it. This means the gene for this trait was "hidden" in the parents, but passed on from each parent to the offspring. Only recessive forms of the gene act like that.
3. Cross Ee with Ee.