Domestic dogs evolved from ancestral gray wolves. Wolves...

Question

Domestic dogs evolved from ancestral gray wolves. Wolves have coats of short, straight hair and lack 'furnishings,' a growth pattern marked by eyebrows and a mustache found in some domestic dogs. In domestic dogs, coat variation is controlled by allelic variation in three genes. Recessive mutant alleles in the FGF5 gene result in long hair, while dogs carrying the dominant ancestral allele have short hair. Likewise, recessive mutant alleles in the KRT71 gene result in curly hair, whereas dogs with an ancestral dominant allele have straight hair. Dominant mutant alleles in the RSPO2 gene cause the presence of furnishings, while dogs homozygous for the ancestral recessive allele have no furnishings. A pure-breeding curly- and long-haired poodle with furnishings was crossed to a pure-breeding short- and straight-haired border collie lacking furnishings

If dogs of the F₁ generation are interbred, what proportions of genotypes and phenotypes are expected in the F₂?

Accepted Answer

Hey, everyone. Let's take a look at this question together. A try. Hybrid cross is performed between two individuals. Each with the genotype. Big a little A big B little B and big C little C. What is the fanatic ratio of this cross expected to be? So, since we're crossing two individuals that each have the genotype of big a little A big B little B and Big C little C or the hetero sickness. For each trait, we know that we are going to have a 3 to 1 ratio for each since both the whole music is dominant and the heterocyclic are expressed the same. So, since the hetero, I guess, and the home is, I guess dominant are expressed the same. We will use a dash as a way to identify both the hetero sickness and the helmet is dominant after each respective letter. For example, A will be identified as a dash to represent both the hedgerows, Agus and the whole music is dominant. So starting off with a, we have a dash which again represents the hetero and homosexuals dominant as well as the Hamas Agus recessive, which is a little, a little a which are the two phenotype we get when we cross each individual or trade A and then when we go to trade be each has two. So we have a dash and a dash as well as little, a little, a little, a little A which trade B is represented as B dash or little B, little B or both. Since we have both the homosexuals and heterosexuals dominant together. And the home is, I guess, recessive. And so lastly, we have C which we know we have C dash little C, little C and then we can just go ahead and fill it out for all the others since each level will have both the homosexuals and heterosexuals dominant as well as the homosexual recessive. And so this is what our cross looks like at the end of the cross between each individuals. And we have a total of eight different phenotype which are represented as the following and each crosses ratio is the following as well. So when we add everything up to get the ratios for each phenotype, we end up with the following fanatic ratios which when we combine them, we have or this as our total fanatic pick ratio, which is answer choice D the correct answer because when we do that try, hybrid cross between the two individuals, each with the genotype, big, a little A big B, little B and big C little C Phan, a typical ratio of the Cross is expected to be 27 to to 9 to 9 to 3 to 3 to 3 to 1. As our in a typical ratio or answer choice. D the correct answer, I hope you found this video to be helpful. Thank you and goodbye.

Key Concepts

Genetic Inheritance

Alleles and Gene Variants

Punnett Squares

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