Concept explainers
In cocker spaniels, solid coat color is dominant over spotted coat color. If two heterozygous dogs were crossed to each other, what would be the probability of the following combinations of offspring?
A. A litter of five pups, four with solid fur and one with spotted fur.
B. A first litter of six pups, four with solid fur and two with spotted fur, and then a second litter of five pups, all with solid fur.
C. A first litter of five pups, the firstborn with solid fur, and then among the next four, three with solid fur and one with spotted fur, and then a second litter of seven pups in which the firstborn is spotted, the second born is spotted, and the remaining five are composed of four solid and one spotted animal.
D. A litter of six pups, the firstborn with solid fur, the second born spotted, and among the remaining four pups, two with spotted fur and two with solid fur.
To review:
The probability of the following combinations of offspring on crossing two heterozygous cocker spaniel dogs:
Five pups, four with solid fur and one with spotted fur.
First litter with six pups, out of which four have solid fur and two have spotted fur, followed by a second litter with five pups, all having solid fur.
First litter with five pups, in which the firstborn has solid fur and among the rest, three have solid fur and one has spotted fur, followed by a second litter with seven pups, in which the first and second born pups are spotted and among the rest, four have solid fur and one has spotted fur.
Six pups, in which the first born has solid fur, the second born has spotted fur, and among the rest, two have solid fur and two have spotted fur.
Introduction:
The coat color in the cocker spaniel can be either solid or spotted. The coat colors are dependent on what genes are passed through the generations in the cocker spaniel. There is one gene responsible for the coat color, which has one dominant allele (B) and one recessive allele (b).
Explanation of Solution
A cross between two heterozygous cocker spaniel dogsproduced the following offspring in the F1 generation.
Alleles involved: B (dominant), b (recessive)
Parental genotypes: Parent 1 = Bb (solid coat color), Parent 2 = Bb (solid coat color)
Gametes | B | b |
B | BB (solid coat color) | Bb (solid coat color) |
b | Bb (solid coat color) | Bb (spotted coat color) |
Five pups, four with solid fur and one with spotted fur.
The probability can be calculated using the binomial expansion method which uses the following equation:
According to the question, the total number of pups is five. So, n = 5.
The number of solid pups is four. So, x = 4.
From the cross between the heterozygous parents, the probability of having an offspring with solid coat coloris
Putting these values in the binomial equation,
First litter with six pups, out of which four have solid fur and two have spotted fur, followed by a second litter with five pups, all having solid fur.
In this question, for the first litter, the values that are to be substituted are as follows:
n = 6, x = 4, p =
Putting the values in the binomial equation,
For the second litter, the values that are to be substituted are as follows:
n = 5, x = 5, p =
Putting the values in the binomial equation,
Multiplying the probability of offspring in both the litters, the total probability comes out to be:
First litter with five pups, in which the first-born has solid fur and among the rest, three have solid fur and one has spotted fur, followed by a second litter with seven pups, in which the first and second-born pups are spotted and among the rest, four have solid fur and one has spotted fur.
In the first litter, the probability of having a pup with solid fur is
The values to be substituted in the equation for the rest of the pups are as follows:
n = 4, x = 3, p =
Total probability of offspring in the first litter:
In the second litter, the probability of the first two pups having spotted fur is
The values to be substituted in the equation for the rest of the pups are as follows:
n = 5, x = 4, p =
Total probability of offspring in the second litter:
Final probability of both the litters combined comes out to be:
Six pups, in which the first-born has solid fur, the second-born has spotted fur and among the rest, two have solid fur and two have spotted fur.
The probability of the first-born pup having solid fur =
The probability of the second-born pup having spotted fur =
The values to be substituted in the equation for the rest of the pups are as follows:
n = 4, x = 2, p =
The probability of having the given offspring becomes:
Therefore, it can be concluded that the probability of the given combination of offspring is:
Five pups, four with solid fur and one with spotted fur = 39.5%
First litter with six pups, out of which four have solid fur and two have spotted fur, followed by a second litter with five pups, all having solid fur = 7.01%
First litter with five pups, in which the firstborn has solid fur and among the rest, three have solid fur and one has spotted fur, followed by a second litter with seven pups, in which the first and second born pups are spotted and among the rest, four have solid fur and one has spotted fur = 1.54%
Six pups, in which the first born has solid fur, the second born has spotted fur and among the rest, two have solid fur and two have spotted fur = 3.95%
Want to see more full solutions like this?
Chapter 2 Solutions
Genetics: Analysis and Principles
- If black and white true-breeding mice are mated and the result is all gray offspring, what inheritance pattern would this be indicative of? a. dominance b. codominance c. multiple alleles d. incomplete dominancearrow_forwardA walnut comb rooster is mated to three hens. Hen A, which has a walnut comb, has offspring in the ratio of 3 walnut to 1 rose. Hen B, which has a pea comb, has offspring in the ratio of 3 walnut to 3 pea to 1 rose to 1 single. Hen C, which has a walnut comb, has only walnut comb offspring. What are the genotypes of the rooster and the three hens?arrow_forwardWhich of the following statements incorrectly illustrates incomplete dominance? Select one: a. Dark brown fur crossed with white fur produces yellow fur. b. Tall plants crossed with short plants produce medium height plants. c. A black horse crossed with a white horse produces a mixture of white and black hair in a horse. d. Red flowers crossed with white flowers produce pink flowersarrow_forward
- black skin is dominant to pink skin color in pigs. two heterozygous black pigs are crossed a. what is the probability that the first and second offspring will have black skin b. what is the probability that their offspring will have pink skin c. if they have a total of 3 piglets, what is the probability that all 3 of them will have black skinarrow_forwardYou are a cat breeder and was asked to choose two parents (male and female) among a group of cats with different coat colors: black, orange and calico. What coat color parents (male and female) would you choose to maximize the chance of getting calico kittens in a litter? Illustrate and explain your choice with the selected cross and outcomes.arrow_forwardBased on the allelic gene interaction in Australian milking shorthorn cattle breeds, the mating of a red cattle (RR) and white cattle is depicted in the picture below. What is gene interaction involved in this resulting coat color of the offspring? see photo attached a. Complete dominance b. Incomplete dominance c. Codominance d. Additive gene actionarrow_forward
- In cats, the allele (B) produces black color but (b) produces a yellow color. These alleles are incompletely dominant to each other. A heterozygote produces a tortoiseshell color. The alleles (B) and (b) are sex-linked as well Cross a tortoiseshell female with a yellow male. a. What percent of their offspring will be yellow? b.What percent of their offspring will be black? c.What percent of their offspring will be tortoiseshell? d.Why is it impossible to have a tortoiseshell male offspring?arrow_forwardPerform the following crosses: A. If having a widow's peak is dominant to having a straight hair line. What percentage of the offspring of a heterozygote with a homozygous recessive will have a widow's peak? B. Using what you have learned, predict the phenotypes of the offspring in this cross. G = grey g= brown L = long hair A GGLL mates with a ggll. 1 = short hairarrow_forwardIn certain species of flies, eye color is controlled by sim-·ple dominance by a single pair of alleles. A red-eyed fly was crossed with a white-eyed fly, both of whose parents had white eyes. All of their offspring (both female and male) had red eyes.a. Which is dominant, the allele for red eyesor the allele for white eyes?b. What is the genotype of the white-eyed parents?c. If the white-eyed parent was mated with one of the red-eyed offspring, what phenotypic ratio wouldyou expect regarding eye color?arrow_forward
- In a certain species of dogs, long hair (L) is domiant to short hair (l). Cross two heterozygotes. a. What is the probability of an offspring with long hair? b. What is the probability of an offspring with short hair?arrow_forwardIn mice black fur (B) is dominant over white fur (b). What is the phenotypic percentage of offspring from a cross between a heterozygous black mouse and a white mouse? 100% black; 0% white 50% black; 50% white 100% gray 75% black; 25% whitearrow_forwardIn cattle, coat color is controlled by a sex-influenced gene that controls spot coloration. Mahogany and white spots are recessive in bulls, where as red-and-white spots is dominant in cows .A mahogany and white spotted cow is crossed with a red-and white spotted bull. The cow gives birth to a single calf with red-and-white spots. a. What are the genotypes of the cow, the bull, and the calf? Use H for dominant and h for recessive. Cow Bull Calf b. The red calf is eventually crossed with a heterozygous male. What is the probability that the first 3 calves will be mahogany with white spots? c. What is the probability that the cross in “b” will result in the first 3 calves being males with mahogany and white spots and the 4th calf a female with red and white spots?arrow_forward
- Concepts of BiologyBiologyISBN:9781938168116Author:Samantha Fowler, Rebecca Roush, James WisePublisher:OpenStax CollegeBiology (MindTap Course List)BiologyISBN:9781337392938Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. BergPublisher:Cengage Learning