In a unique species of plants, flowers may be yellow, blue, red, ...

Question

In a unique species of plants, flowers may be yellow, blue, red, or mauve. All colors may be true breeding. If plants with blue flowers are crossed to red-flowered plants, all F₁ plants have yellow flowers. When these produced an F₂ generation, the following ratio was observed:

9/16 yellow: 3/16 blue: 3/16 red: 1/16 mauve

In still another cross using true-breeding parents, yellow-flowered plants are crossed with mauve-flowered plants. Again, all F₁ plants had yellow flowers and the F₂ showed a 9:3:3:1 ratio, as just shown.

Describe the inheritance of flower color by defining gene symbols and designating which genotypes give rise to each of the four phenotypes.

Accepted Answer

Hi everyone, welcome back. Here's our next question. It says the purple capital p flowers dominate over the white little pea flowers. If we cross to hetero parents, what would be the resulting Jenna typical ratio of the offspring. So things to keep in mind here, we have our dominant allele of purple trait. The recessive value of the white trait. We're gonna have a hetero sickos cross. So the parents are going to look like big p little P across the big p little P. And we're looking for the genotype ratio, not the phenotype ratio. Always good to keep that in mind. Although if we look here at our answer choices, we'd see that we have three different numbers. If you were looking for a fanatic offering, well, there's only phenotype ratio. There's only two different phenotype is purple and white. We only see two numbers. Um but in some cases where it might not be that clear, make sure you know which type of ratio you're looking for phenotype versus genotype. So let's just put up a very quick and easy pundit square here, we've just got one trait. So very simple. We've got two hetero parents. And so we see we end up with two possibilities for hetero sickness offspring. We've got one possibility for homicide is dominant and one recessive. So our genotype ratio here will be 1 to 2 to one with the ones being the home of cigarettes and two heterocyclic. It's so we'll go over to our answer choices and we see that's choice B And those ratio numbers, are you talking about Jenna types here with a single trait? That will be the order in which you'd write it in. So you'd have homocide guess dominant first and then hetero sickness in the middle and Hamas I guess recessive at the end. This is a good ratio to just be really, really familiar with. As that's the kind of basic cross that you'll often encounter. So again, when you have a hetero sickos cross for one trait in this case purple dominant and white recessive to hetero sickos, parents are crossed. The resulting Jenna typical ratio of the offspring is choice B, 1 to 2 to one. See you in the next video.

Key Concepts

Mendelian Inheritance

Genotype and Phenotype

Dihybrid Cross and Phenotypic Ratios

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