An experienced goldfish breeder receives two unusual mal...

Question

An experienced goldfish breeder receives two unusual male goldfish. One is black rather than gold, and the other has a single tail fin rather than a split tail fin. The breeder crosses the black male to a female that is gold. All the F₁ are gold. She also crosses the single-finned male to a female with a split tail fin. All the F₁ have a split tail fin. She then crosses the black male to F₁ gold females and, separately, crosses the single-finned male to F₁ split-finned females. The results of the crosses are shown below.

Black male x F₁ gold female:
Gold 32
Black 34
Single-finned male x F₁ split-finned female:
Split fin 41
Single fin 39

Is black color dominant or recessive? Explain. Is single tail dominant or recessive? Explain.

Accepted Answer

Hi, everybody. Let's take a look at this practice problem together. A male mouse with black fur was made into a female mouse with white. For the female produces a litter of 11 pups with six black and five white fur. On the contrary, when another male mouse with black fur was mated with a female mouse with white for the female produced a litter of nine pups with all black fur. If the little fur, black fur is FB and for white is F W identify the gina types of both the males. Now let's summarize the information. We know from the question. Both males meet with white for females, male, one has six black for pups and five white for pups. Mail to has all black for pups. What this means is that it implies that black is the dominant a lil. So black fur is dominant and white fur is recessive. We know all of the females had white fur. So this implies the female genotype is F W F W ho mosaic is recessive. Now back to mail to since he only produced black for pups, we can deduce that his genotype was. Homo Ziggy's dominant or F B F B. We can confirm this by doing a punishment square on the screen. Here we have a punnett square cross between the male and the female. The results are all four offspring have genotype F B F W. So they all are headers aegis and appear with black fur. So this confirms that male two's genotype is F B F B. Now to determine male one's genotype, his offspring had a 1 to 1 phan a typical ratio, which means so 1 to 1 phenotype IQ ratio, which means that some of his pups inherited two recessive white fur seals. His genotype therefore would have been F B F W. Again, we can confirm this using a punnett square cross on the screen. We have the results of the punnett square cross of a male FB F W with female F W F W and you can see that two offspring are F B F W. So headers, Agus with black fur and to R F W F W. So homesickness recessive with white for this confirms the males genotype as F B F W. So male ones genotype is FB F W and male two's genotype is F B F B. Therefore the correct answers. Option B alright, everyone. I hope you found this helpful and I'll see you soon for the next practice problem.

Key Concepts

Dominance in Genetics

Phenotypic Ratios

Genotype and Phenotype

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