Ch 16 Please help with these few problems I have left Your h

Ch. 16 Please help with these few problems I have left. Your help is greatly appreciated. Thank you.

(Problem 30a) Figure 3.8 shows the results of a dihybridcross involving seed shape and seed color. What proportion of the round and yellow F2 progeny fromthis cross is 32. homozygous at both loci? Experiment Question: Do alleles encoding different traits separate independently? (a) Methods P generation Round, yellow wrinkled, green n RRYY Gametes RY Fertilization b) Round, yellow generation seeds Gametes RY (ry Ry Orr Self-fert zation (c) Results F2 generation RY Rrry Rryy rri rryy Phenotypic ratio round, yellow: 3 round, green 3 wrinkled, yellow 1 wrinkled, green Conclusion: The allele encoding color separated independently of the allele encoding seed shape, producing a 9:3:3:1 ratio in the F2 progeny. Figure 3.8 Genetics Essentials: Concepts and Connections Third Edition O 2016 Macmillan Education A. 1/9 B. 3/9 C C. 5/9 D. 7/9 C E. 9/9

Solution

32. Answer. C 5/9

Alternative forms of a given gene are called alleles (Y and y are alleles of the gene for seed colour)
They can be dominant (Y) or recessive (y).
When an individual has two of the same allele, whether dominant (YY) or recessive (yy), they are homozygous

The results of dihybrid cross between F1 heterozygotes (RrYy x RrYy) are shown in Checkerboard.

The proportion of Round and Yellow in F2 progeny, as seen from the Checkerboard is as

RRYY, rryy, rryy, RRyy, rryy

Therefore, the answer is C. 5/9