A dark-red strain and a white strain of wheat are crossed and produce an intermediate, medium-red F₁. When the F₁ plants are interbred, an F₂ generation is produced in a ratio of 1 dark-red: 4 medium-dark-red: 6 medium-red: 4 light-red: 1 white. Further crosses reveal that the dark-red and white F₂ plants are true breeding
Based on the ratios in the F₂ population, how many genes are involved in the production of color?

Question

A dark-red strain and a white strain of wheat are crossed and produce an intermediate, medium-red F₁. When the F₁ plants are interbred, an F₂ generation is produced in a ratio of 1 dark-red: 4 medium-dark-red: 6 medium-red: 4 light-red: 1 white. Further crosses reveal that the dark-red and white F₂ plants are true breeding
Based on the ratios in the F₂ population, how many genes are involved in the production of color?

Based on the ratios in the F₂ population, how many genes are involved in the production of color?

Accepted Answer

Hey everyone. Let's take a look at this question together. Which of the following differences between the additive and the non additive gene action is false. So let's recall what we've learned about additive gene action and non additive gene action to figure out which of the following differences is false. So we know that additive gene action refers to both alleles expressed equally, meaning they share that expression. Whereas in the non additive gene action, the alil with the stronger dominance is the one that is expressed so stronger dominance is expressed. And so looking at the following differences, answer choice A says additive gene action does not show any dominance. Whereas non additive gene action shows complete dominance or incomplete dominance. Now we know that this statement is a true statement because in that additive gene action we have that equal expression. So there is no dominance. And in that non additive gene action, the one that is stronger is the one that shows up. So you either have complete dominance or incomplete dominance. So answer choice A is a true statement and is an incorrect answer. Looking at answer choice B. It says an additive gene action. Both alleles are expressed equally. Whereas in non additive gene action, only one allele is expressed stronger than the other. Which we know is also a true statement because we have that equal expression in an and we only have one allele that is expressed in non additive because of that complete dominance or incomplete dominance. So answer choice B is an incorrect answer because it is a true statement. And lastly answer choice C says the additive illegal does not contribute to the phenotype. Whereas the non additive allele contributes to the phenotype. We note that this statement is incorrect because the additive alil is the one that contributes to the phenotype, whereas the non additive alil is the one that does not contribute to the phenotype. So answer choice C. Is a false statement, making it the correct answer to this question. Because we know that additive gene action is the one where both alleles are expressed equally and non additive gene action is the one where the stronger dominant allele is the one that is expressed. So answer Choice C. Is the correct answer. I hope you found this video to be helpful. Thank you and goodbye.

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Key Concepts

Incomplete Dominance and Intermediate Phenotypes

Polygenic Inheritance and Quantitative Trait Ratios

True Breeding and Homozygosity