In the parakeet, two unlinked autosomal gene loci produce feather pigment. Allele B at one locus produces a blue pigment. Allele Y at the other locus produces a yellow pigment. Recessive, loss-of-function alleles exist at each locus which prevent their respective pigments from forming properly. Two green parakeets are mated and produce green, blue, yellow and white progeny. Based on this information, explain the inheritance of feather coloration in these parakeets including:

a. the parental genotypes

b. the general genotypic formulae for green, blue, yellow, and white parakeets

c. the expected phenotypic ratio of offspring from this type of parental cross.

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Question 12 and 13: Consider the biochemical pathway presented below. This pathway determines pigment production in pea flowers. (Note: gene products are required for each reaction to proceed.)

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A. Yes B. No C. Insufficient information to determine

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A. 9:3:3:1 (blue : green : yellow : white) B. 9:3:4 (blue : green : white) C. 9:7 (blue : white) D. 15:1 (blue : white)

14. How can haplosufficiency explain dominance of an allele that codes for a functional protein over a null (loss of function) allele?

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A. Ab/ab 390 aB/ab 410 AB/ab 350 ab/ab 420

B. Ab/ab 80 aB/ab 73 AB/ab 760 ab/ab 754

C. Ab/ab 700 aB/ab 695 AB/ab 56 ab/ab 59

D. Ab/ab 400 aB/ab 65 AB/ab 50 ab/ab 659