Biology Forums - Study Force

Biology-Related Homework Help Genetics and Developmental Biology Topic started by: smmcmahon35 on Sep 5, 2012



Title: 4. You have two purple?flowered pea plants where purple is made by the P allele?
Post by: smmcmahon35 on Sep 5, 2012
4. You have two purple?flowered pea plants where purple is made by the P allele
while white flowers are made by the p allele. P is dominant over p. When you cross
these two plants you get a 3:1 ratio of purple:white flowered offspring. What are
the genotypes of the parents?


Title: 4. You have two purple?flowered pea plants where purple is made by the P allele?
Post by: oapplesauce on Sep 5, 2012
Both parents are Pp.

Pp x Pp makes

PP, Pp, Pp, pp

which are

purple, purple, purple, white phenotypically (3:1 purple:white)


Title: 4. You have two purple?flowered pea plants where purple is made by the P allele?
Post by: Miguel2233 on Sep 5, 2012
Most likely both parents are heterozygous, that is Pp.  This type of cross (monohybrid) usually results in a 3:1 ratio (dominant to recessive) in the offspring in the F2 generation.