Genetics- mono and dihybrid crosses

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In summary, the conversation discusses the challenge of finding a genotype that will result in a 3:1 ratio in genetics homework. The speaker initially considers a mono hybrid cross but later suggests that it could be a dihybrid cross. They mention the possibility of using epistasis to solve the problem and also mention another ratio (13:3) that they are struggling with.
  • #1
MitsuShai
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There is one part that I can't figure out the answer to on my genetics homework which is finding out what genotype will give 3:1 . I've tried using so ways but I really think getting those ratios is impossible; I honestly don't see any way but I really don't want to right that down. I was at first thinking that 3:1 has to be a mono hybrid cross but now I'm thinking that 3:1 can somehow be a dihybrid cross (if you reduce the numbers or something). I honestly can't get a genotype for this.
 
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  • #2
Crossing Aa with Aa where a is recessive gives phenotypes in 3:1 ratio and this is elementary, but maybe that is not your question, actually

MitsuShai said:
out what genotype will give 3:1 .

does not seem very clear or meaningful.
 
  • #3
epenguin said:
Crossing Aa with Aa where a is recessive gives phenotypes in 3:1 ratio and this is elementary, but maybe that is not your question, actually



does not seem very clear or meaningful.


yeah I know that, I was asking for how the genotype can be 3:1


I think it has something to do with epistasis.
There was another ratio on my homework that was tough to figure out and it was finding the genotypes that can lead to a 13:3 ratio. I applied epistasis and I got Ww+bb+ x Ww+bb+ as my answer but then I thought about this for a second and I am not thinking that that cross does not give me the genetic ratio but the phenotypic ratio...I don't know anymore, can anybody help?
 

FAQ: Genetics- mono and dihybrid crosses

1. What is the difference between mono and dihybrid crosses?

Mono and dihybrid crosses are both types of genetic crosses used to study the inheritance of traits in offspring. The main difference is that mono crosses involve one gene and two alleles, while dihybrid crosses involve two genes and four alleles. This means that dihybrid crosses are more complex, as they involve the inheritance of two traits at once.

2. How do you determine the genotypes and phenotypes of offspring in a mono or dihybrid cross?

In a mono or dihybrid cross, the genotypes and phenotypes of offspring can be determined using a Punnett square. The Punnett square is a grid that helps predict the possible combinations of alleles that can be inherited from the parents. By filling in the Punnett square with the genotypes of the parents, you can determine the genotypes and phenotypes of the offspring.

3. What is the purpose of performing a mono or dihybrid cross?

The purpose of performing a mono or dihybrid cross is to study the inheritance of traits in offspring. By crossing organisms with known genotypes, we can make predictions about the genotypes and phenotypes of their offspring. This can help us understand how traits are inherited and how genetic diseases are passed down from parents to offspring.

4. Can mono and dihybrid crosses be used to study traits in humans?

Yes, mono and dihybrid crosses can be used to study traits in humans. While it is not ethical or practical to perform genetic crosses in humans, scientists can use data from family pedigrees to make predictions about the inheritance of traits and genetic diseases in humans. This information can help identify individuals who may carry genetic diseases and inform genetic counseling.

5. Are there any limitations to using mono and dihybrid crosses in genetics research?

Yes, there are some limitations to using mono and dihybrid crosses in genetics research. One limitation is that these crosses only take into account the inheritance of one or two traits at a time, while many traits are actually influenced by multiple genes. Additionally, environmental factors can also play a role in the expression of traits, which may not be reflected in a genetic cross. Therefore, other methods, such as genome-wide association studies, may be needed to fully understand the complex inheritance of traits in organisms.

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