In Labrador retrievers, there are 3 gene products involved in determining coat color: gene product B, gene...

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.

Expert Solution

In this question, I've first remove CC from the genotype because both the parents are homozygous recessive for CC which means that every offspring will be CC genotype only. This reduces the number of punett square as with 3 genes, punett square have 64 boxes and even in the question, it is asked for 16 boxes which comes from a dihybrid cross. So don't think it's wrong or there's a mistake. Basically we can safely assume everyone will have CC gene product.

In the above image, I've performed punett square for the parental genotypes.

I'll attach another image below with every box written on top what will be the phenotype for better understanding.

In this image I've written down the phenotype over the genotype. For example, the first offspring is BBEE and the phenotype written over it is Black.

Now as for the ratio of phenotype is :-

9 Black : 3 Chocolate : 4 Yellow

Question b) Type of genetic phenomenon occuring here with Respect to E.

The answer is Epistasis. Epistasis is occuring here because in Epistasis expression of one gene is dependent on other genes' expression and if other genes are not expressed they will affect the phenotype of the genes in questions. In our question, even though BB alleles are present, Labrador is Yellow because ee is homozygous recessive and even though Black pigment is produced by BB gene, mutation in E gene is affecting the Black colour expression.

gladiator answered 2 years ago

In Labrador retrievers coat color is controlled by two independently assorting loci. The B locus controls...

In Labrador retrievers coat color is controlled by two independently assorting loci. The B locus controls hair color; black (B) is dominant to chocolate (b). A second locus, E, allows for deposition of the color on the hairs. The homozygous recessive condition at this locus (ee) produces a yellow dog, regardless of whether the animal is BB, Bb, or bb. You discover that your female yellow Labrador is pregnant, and she delivers a litter of 5 black puppies, 2 chocolate...

1. In mice, one of the gene determining coat color is the A gene, which has...

1. In mice, one of the gene determining coat color is the A gene, which has multple alleles. two of these are an Allele for black hair (a) and allele for yellow hair (Ay) . (Ay) is completely dominant to a; however, for reasons that are unclear ( at least to me), AYAY mice always die before embroyic development is completed. a) two mice with yellow hair mate with each other. what are the genotype of the mice? b) for...

Mendelian genetics predict that in Labrador retrievers (a type of dog), 25% should have brown coat...

Mendelian genetics predict that in Labrador retrievers (a type of dog), 25% should have brown coat color if both parents are heterozygous (the rest are black). You mate two parents and get a litter of 8 puppies. Calculate the following: a) The probability of 6 black puppies. b) The probability of 3 brown puppies. c) The probability that 50% of the puppies will be brown. (Comment: You do not need to know anything about genetics to solve this problem. If...

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...

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. Determine the genotypes of parents of litters with the following phenotype distributions. Part A...

In mice the allele for blue coat color (B) pink coat color (b). The allele for...

In mice the allele for blue coat color (B) pink coat color (b). The allele for long tail (T) is dominant of the allele for short tail (t). 1) If alleles of the two genes Assort Independently, what types of gametes will BbTt mice produce? What is the expected frequency of each gamete among all gametes produced?

1. In cats, coat color is controlled by a gene on the X chromosome. Yellow coat...

1. In cats, coat color is controlled by a gene on the X chromosome. Yellow coat color is determined by the b allele and black coat color is determined by the B allele. The heterozygous condition results in a color known as tortoise shell. a. What phenotypic ratio of offspring would be expected from a cross between a yellow male and a tortoise-shell female? b. What proportion of the female offspring from a cross between a black female and a...

Labrador retriever dogs have three coat colors: black, brown and yellow. The color of the pigment...

Labrador retriever dogs have three coat colors: black, brown and yellow. The color of the pigment deposited in the hairs is determined by a gene with two alleles (B or b). The B allele codes for black pigment and is dominant to the b allele which codes for brown. Another gene with two alleles (E or e) determines if the pigment created will be deposited into the hairs. If both copies (ee) are recessive, no pigment will be deposited (regardless...

Coat color in rodents is known to be a trait resulting from gene interactions (gene modifier...

Coat color in rodents is known to be a trait resulting from gene interactions (gene modifier effect). The two genes involved are A and C. Allele C results in black pigmentation and is dominant to c (albino). Allele A results in the agouti phenotype if the rodent carries at least one dominant C allele. One albino rodent from unknown genotype mates an agouti rodent that is known to be homozygous dominant for both genes. The offspring resulting from that mating...

answer use a different color, please) 1. In shorthorn cattle the gene for red coat color...

answer use a different color, please) 1. In shorthorn cattle the gene for red coat color is not dominant over that for white coat color. The heterozygous condition produces a roan color. A breeder has a white, red, and roan cows and bulls. What phenotypes can be expected from the following crosses? A. Red x roan B. Red x red C.. Roan x white D. Red x white 2. A homozygous black chicken is crossed with a homozygous splashed white...

Question