Question

QUESTION 15 In Labrador retrievers, there are 3 gene products involved in determining coat color: gene product B, gene product E, and gene product C. B produces a melanin pigment such that B/B and B/b will produce a black lab while b/b (with less melanin produced) will result in a chocolate lab. However, for the B gene to be expressed, a signaling hormone (gene E product) must be produced to activate transcription of the B gene. E is fully dominant to e (loss of function mutation). In the absence of the hormone, a yellow lab will result (due to the pigment product of the C gene). What are the ratios of black, chocolate, and yellow labs that will be produced from a BbCCEe x BbCCEe cross? Hint: set up a Punnett square and determine the phenotypes of each of the 16 boxes. What type of genetic phenomenon is occurring here with respect to the E gene? Explain why you think this is. RIC TT T Arial + 3(12pt) TEE Words:0 Path:p QUESTION 16

Answer 1

are- Black B Ce (15) P2 - selfing - genotype - Bb CC Ee, possible gamets BCE, bCE, Ble, ble 50, P, XPBb CC Ee X Bb CC Ee. Punnett BCE b CE B Ce b Ce square BCE BB CCEE Bь СcЕЕ BBCC Ee ВЬ СС Ее Black Black Black, ICE BbCCEE bb CC EE Bb CC Te bb CC Ee Black Chocolate Black Chocolate BB CC Ee Bb CC Ee BB clee Bbccee Black Black Yellow Yellow ble ВЬССЕe bbcc te B belee bb Clee Black Chocolate Yellow Yellow genetic phenomenon observed, here is a case recessive ebistasis with res bect to Egene, Dj is because recessive allele for Egene suppress the activity of B gene and thus C gene get to expressed itself; and also phenotypic ratio Black (9) ! Chocolate (3): Yellow (4) indicate the same ratio as of recessive ebistasis condition, The مت