In a cross between a black and a white guinea pig, all members of the F₁ generation are black. The F₂ generation is made up of approximately 3/4 black and 1/4 white guinea pigs. Two different matings were made between black members of the F₂ generation, with the following results. Diagram each of the crosses.
Cross Offspring
Cross 1 All black
Cross 2 3/4 black, 1/4 white

Question

In a cross between a black and a white guinea pig, all members of the F₁ generation are black. The F₂ generation is made up of approximately 3/4 black and 1/4 white guinea pigs. Two different matings were made between black members of the F₂ generation, with the following results. Diagram each of the crosses.

Cross Offspring

Cross 1 All black

Cross 2 3/4 black, 1/4 white

Accepted Answer

Hi everyone. Let's take a look at this practice problem. We have tall big ap plants are dominant over short little ap plants. If a hetero sickos pea plant is allowed to self fertilize which of the genotype has a 50% probability of appearing in the F one generation. So we need to know the gina types when two hetero sickos pea plants self fertilize. Now recall that hetero means different. So the wheels for the heterocyclic sp plant will be different and we will have big a little A representing the hetero CSP plant. And so it will self fertilized with another plant looking exactly the same. Big a little A. Now, if we do this cross, we get the following punnett square result and we can see That we have four different offspring And we need to know which of those Jenna types has a 50% probability of a period. So let's go ahead and take a look at our possible answer choices for a. We have a big a big a genotype And we can see from our opponents where results that there is one of those. So that's one out of four giving us 25% probability and we need 50%. So we can eliminate option a. If we look at option B, we have little a little a genotype and there is one out of four of those as well. Again giving us only 25% probability and we can eliminate option B. If we take a look at options, see the big a little a genotype, let's take a look at the planet squares, There's two out of four possibilities or one half, which is 50 And that is what we are asked in the practice problem. The genotype that has a 50% probability. Therefore, C. big a little a genotype is our answer, and we can automatically eliminate option D. All options are correct because we know that's not correct. Alright, everyone. I hope you guys found this helpful and I'll see you for the next practice problem.

In a cross between a black and a white guinea pig, all members of the F₁ generation are black. The F₂ generation is made up of approximately 3/4 black and 1/4 white guinea pigs. Diagram this cross, showing the genotypes and phenotypes.

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Key Concepts

Mendelian Inheritance

Punnett Square

Genotype vs. Phenotype