## MidoriKeehl 2 years ago In pea plants purple flowers are dominant over white flowers. If you cross a heterozygous purple flower plant with a white flower plant what are the expected genotypes and phenotypes of the offspring? Report your answer for both genotype and phenotype stating the fractions of each that are expected

1. blues

The first step is to write out the parents genotypes. In this case, it tells you that the purple parent is heterozygous, meaning that it has one allele of each type. So Pp. Furthermore, it tells you that purple is dominant over white, so if the white parent had even one dominant allele it would be purple. Its phenotype is pp. Those are what you should use when you set up your Punnet Square. Hopefully that is enough to get you started. :)

2. MidoriKeehl

Can you help me with the fraction part? o:

3. blues

Before you can get to the fractions, you have to do a Punnet square. Have you already done that part on your own or shall we work through it here?

4. MidoriKeehl

It would be Pp and ww so it would be like.. so would it be like 50/50?

5. MidoriKeehl

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6. MidoriKeehl

sorry I drew it but it didnt come out on the other one

7. blues

That is exactly right. The only slightly, erm, irregular thing about it is that you have assigned a big P for the dominant purple allele and a lower case w for the recessive white allele. Tradition has it that the alleles are both the same letter but the dominant one is capital P and the recessive one is lowercase p. That is just a matter of naming. And the ratios are quite correct. Using your notation, the 1/2 Pw offspring are heterozygous - they have a dominant allele, P, so they will be purple. While the 1/2 pw offspring have only the recessive allele, so they will all be white.

8. MidoriKeehl

Okay, thank you very much!

9. blues