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In rats, gene B produces black coat color if the genotype is B-, but black pigment...

In rats, gene B produces black coat color if the genotype is B-, but black pigment is not produced if the genotype is bb. At an independent locus, gene D produces yellow pigment if the genotype is D-, but no pigment is produced when the genotype is dd. Production of both pigments results in brown coat color. If neither pigment is produced, coat color is cream. A third independently assorting gene involved in determination of coat color in rats is the C gene. At this locus, the genotype C- permits expression of pigment from genes B and D. The cc genotype, however, prevents expression of coat color and results in albino rats. For each of the following crosses, determine the expected phenotypes and their ratio in progeny: Express your answer as five numbers separated by colons. If there is no progeny of a particular phenotype, enter zero.

A. BbDDCc ×× BbDdCc

B. BBDdcc ×× BbddCc

C. bbDDCc ×× BBddCc

D. BbDdCC ×× BbDdCC

Expert Solution

A_bbC_ = Black coat color

aaB_C_ = Yellow coat color

A_B_C_ = Brown coat color

aabbC_ = cream coat color

____cc = Albino rats

A) BbDDCc ×× BbDdCc

BbDDCc ×× BbDdCc	BDC	BDc	BdC	bDC	Bdc	bDc	bdC	bdc
BDC	BBDDCC (brown)	BBDDCc (brown)	BBDdCC (brown)	BbDDCC (brown)	BBDdCc (brown)	BbDDCc (brown)	BbDdCC (brown)	BbDdCc (brown)
BDc	BBDDCc (brown)	BBDDcc (albino)	BBDdCc (brown)	BbDDCc (brown)	BbDdcc (albino)	BbDDcc (albino)	BbDdCc (brown)	BbDdcc (albino)
bDC	BbDDCC (brown)	BbDDCc (brown)	BbDdCC (brown)	bbDDCC (yellow)	BbDdCc (brown)	bbDDCc (yellow)	bbDdCC (yellow)	bbDdCc (yellow)
bDc	BbDDcc (albino)	BbDDcc (albino)	BbDdCc (brown)	bbDDCc (yellow)	BbDdcc (albino)	bbDDcc (albino)	bbDdCc (yellow)	bbDdcc (albino)

0 (black): 6 (yellow) : 17 (brown) : 0(cream) : 9 (albino)

Ratios - 0 : 6/32 : 17/32 : 0 : 9/32

B) BBDdcc ×× BbddCc

BBDdcc ×× BbddCc	BdC	bdC	Bdc	bdc
BDc	BBDdCc (brown)	BbDdCc (brown)	BBDdcc (albino)	BbDdcc (albino)
Bdc	BBddCc (black)	BbddCc (black)	BBddcc (albino)	Bbddcc (albino)

2 (black): 0 (yellow) : 2 (brown) : 0(cream) : 4 (albino)

Ratios- 2/8 : 0 : 2/8 : 0 : 4/8

C) bbDDCc ×× BBddCc

bbDDCc ×× BBddCc	BdC	Bdc
bDC	BbDdCC (brown)	BbDdCc (brown)
bDc	BbDdCc (brown)	BbDdcc (albino)

0 (black): 0 (yellow) : 3 (brown) : 0(cream) : 1 (albino)

Ratios- 0: 0 : 3/4 : 0 : 1/4

D) BbDdCC ×× BbDdCC

BbDdCC ×× BbDdCC	BDC	BdC	bDC	bdC
BDC	BBDDCC (brown)	BBDdCC (brown)	BbDDCC (brown)	BbDdCC (brown)
BdC	BBDdCC (brown)	BBddCC (black)	BbDdCC (brown)	BbddCC (black)
bDC	BbDDCC (brown)	BbDdCC (brown)	bbDDCC (yellow)	bbDdCC (yellow)
bdC	BbDdCC (brown)	BbddCC (black)	bbDdCC (yellow)	bbddCC (cream)

3 (black): 3 (yellow) : 9(brown) : 1(cream) : 0 (albino)

Ratios- 3/16 : 3/16 : 9:16 : 1/16 : 0

gladiator answered 2 years ago

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