Question

In: Biology

In cats with tortoiseshell coat color, the fur is white with patchy black and orange spots....

In cats with tortoiseshell coat color, the fur is white with patchy black and orange spots. In cats, the tortoiseshell gene is on the X chromosome, and the tortoiseshell phenotype requires the presence of 2 different alleles at this locus: one for orange fur (o) and one for black fur (b). Which phenomenon best explains why female cats can inherit tortoiseshell coat color?
(A. In females, the alleles for coat color are pleiotropic, resulting in patches of orange and black coat color.

  
B In females, these coat color alleles show incomplete dominance, but in males, the coat color alleles do not.

       
C Females typically express both the orange and the black allele in each cell (alleles are co-dominant), making orange and black coat color possible.

       
D Females are mosaic with respect to their X chromosomes, because in each cell, one of the X chromosomes is randomly inactivated.)

If a black female cat mates with an orange male cat, what proportion of their female offspring are expected to be tortoiseshell cats?

Solutions

Expert Solution

Question: Which phenomenon best explains why female cats can inherit tortoiseshell coat color?

Answer- D. Females are mosaic with respect to their X chromosomes, because in each cell, one of the X chromosomes is randomly inactivated.

This is the correct option because female cat carry double X linked gene which is linked to coat color  resulting in expressing double dose of X-linked product which is toxic in comparision to male cate who has only one copy of X linked gene. In order to maintain  the balance , the female cat follow the dosage compensation by randomly inactivating anyone X chromosome.

In heterozygous condition, ( Suppose B code for orange color and b code for black color then heterozygous condition will be XBXb in famale cat)

In a patch of skin where the X chromosome carrying the B allele is inactivated , that will express only the b allele and will have black fur.In a patch of skin where the X chromosome carrying the b allele is inactivated, that will express only the B allele and will have orange fur. This is masaic expression of X-linked gene in female cat.

Question:If a black female cat mates with an orange male cat, what proportion of their female offspring are expected to be tortoiseshell cats?

Answer: Suppose B code for orange color and b code for black color,

genotype of black female cat: XbXb

genotype of orange male cat : XBY

XbXb X XBY

genotype of female offspring : XbXB

same proportion of their female offspring are expected to be tortoiseshell cats because all female offspring genotype will be heterozygous so it will express mosaic patterns of X linked gene for coat color.


Related Solutions

In cats, the allele for black coat color is codominant with the allele for yellow coat...
In cats, the allele for black coat color is codominant with the allele for yellow coat color, and is located on the X chromosome. If a cat gets alleles for black and yellow coat, it will have a mottled coat that contains both yellow and black coloring known as Tortoise shell. A tortoise shell female mates with a yellow male. a) What is the genotype of each parent? b) Draw a Punnett square that shows this cross. c) What is...
Lake McMurtry Monsters (LMM) have three different coat color phenotypes (black, orange, and white). Their coat...
Lake McMurtry Monsters (LMM) have three different coat color phenotypes (black, orange, and white). Their coat color is an example of epistasis. The B gene codes for color type while the W gene codes for the presence or absence of color. ‘B’ is completely dominant to ‘b’ and ‘W’ is completely dominant to ‘w’. For a LMM to be black or orange, they must have the ‘W’ allele. Black is dominant to orange. What are the possible genotypes for the...
In Triskelian cats, in the Blondish Galaxy, black coat color is dominant over grey. Coat color...
In Triskelian cats, in the Blondish Galaxy, black coat color is dominant over grey. Coat color is determined by a single autosomal gene with two alleles: B = black coat color; b = grey coat color. The autosomal gene for eye color is hypothesized to assort independently from the gene for coat color. The two alleles are: R = green eye color; r = blue eye color. If a green-eyed black female cat whose mother has a grey coat and...
Black fur color is dominant to white fur color and non-webbed toes are dominant to webbed...
Black fur color is dominant to white fur color and non-webbed toes are dominant to webbed toes. a dog with white fur and web toes is mated with a dog homozygous dominant for both black fur and non-webbed toes. Draw the resulting Punnett square from this cross. What are the genotypic and phenotypic ratios of their offspring.
In mice the allele for black coat color (B) is dominant to the allele for white...
In mice the allele for black coat color (B) is dominant to the allele for white coat color (b). The allele for long tail (T) is dominant to the allele for short tail (t). For the same cross: BbTt x bbTt     a. Using the Probability Method illustrated in lecture, break the complex two-gene cross into two simple single-gene crosses (note that the Probability Method can be used if it is known that the alleles of the different genes Assort...
Calico cats have two genes that govern their coat color. One gene codes for the white...
Calico cats have two genes that govern their coat color. One gene codes for the white undercoat and the other codes for the fur colors black and orange and this gene is X-linked. We will look at the gene for black and orange fur color only. In this situation, both black and orange are codominant, so that heterozygous individuals are a different phenotype. Based on this information, what would black, orange and calico female cats' genotypes be? What would be...
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...
in badgers, fur color is inherited through simple autosomal inheritance, and black fur is dominant to...
in badgers, fur color is inherited through simple autosomal inheritance, and black fur is dominant to white fur. A black badger is crossed with a white badger. In a cete of four kits, all of the kits are black. You have asked to draw a conclusion about the black badger. What is the best conclusion you can draw from this data? a. The black badger is definitely homozygous. b. the black badger is probably homozygous. c. the black badger is...
In foxes, there are 2 genes that we wish to study. For coat color, platinum fur...
In foxes, there are 2 genes that we wish to study. For coat color, platinum fur is dominant to wild-type fur color. For tails, one stripe at the tip of the tail is dominant to solid tail. Perform a cross between a truebreeding wild-type coat color and solid tail fox and a truebreeding platinum coat color, one stripe tail fox. Then take one male and one female of the F1 generation and cross them together. Give the genotype, phenotype, and...
In dogs, solid coat color (S ) is dominant over white spotted coat (s ). In...
In dogs, solid coat color (S ) is dominant over white spotted coat (s ). In a cross between two heterozygous dogs, what would be the probability of having a first litter of six pups, the firstborn with spotted fur, and then among the next five, three with solid fur and two with spotted fur; and then a second litter of seven pups in which the firstborn is spotted, the second born is solid, and then the remaining five pups...
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT