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in tomates the flesh can be either red or yellow. Below is a chart of several cr

ID: 256160 • Letter: I

Question

in tomates the flesh can be either red or yellow. Below is a chart of several crosses and the actual phenotype ratios. Complete the genotype colummns in the table/.

Parent Pheotype Phenotypes of offspring Redxred possible genotypes of parents ? 75 redyellow possible genotypes for the offspring ? Redxred possible genotypes of parents ? 61 red, 19 yellow yellow possible genotypes for the offspring ? Redx yellow possible genotypes of parents ? 68 red yellow possible genotypes for the offspring ? Yellow x yellow possible genotypes of parents ? 84 yellow yellow possible genotypes for the offspring ? Red x yellow possible genotypes of parents ? 49 red, 52 yellow possible genotypes for the offspring ?

Explanation / Answer


a) What phenotype is dominant?
Red is dominant.


b) What are the genotypes of the parents and offspring in each case?
Let R be dominant red allele and let r be the yellow allele.
Cross 1: RR X RR (or r) = Progeny are RR or ½ RR and ½ Rr

Cross 2: Rr X Rr = Progeny are ¼ RR, ½ Rr and ¼ rr

Cross 3: RR X rr = Progeny are all Rr

Cross 4: rr X rr = Progeny are all rr

Cross 5: Rr X rr = Progeny are ½ Rr and ½ rr

Parents Progeny Red x red 75 red yellow Red x red 61 red, 19 yellow Red x yellow 68 red yellow Yellow x yellow 84 yellow yellow Red x yellow 49 red, 52 yellow