A cross between two pea plants with axial flowers and inflated pods gives the following offspringg: 20 with axial flowers and inflated pods, 7 with axial flowers and constricted pods, and 5 with terminal flowers and inflated pods. What is the most probable genotype for the two parents? Explain the results and show the Punnett square. How can the explanation be checked?
10:3.5:2.5
terminal is resessive and so is constricted. Most probable combo is heterozygous. Heteros come out to a 9:3:3:1 ratio. You can check it with that. Its not doing to be exact, but then again nature never is
I have the same question and do not understand it, well i do. Just need help to set it up. Well the punnett square
To determine the most probable genotype for the two parents, we need to analyze the results and use a Punnett square.
Given the offspring ratios:
- 20 with axial flowers and inflated pods
- 7 with axial flowers and constricted pods
- 5 with terminal flowers and inflated pods
We can deduce that the traits for axial flowers and inflated pods are dominant, while the traits for constricted pods and terminal flowers are recessive.
Let's use symbols to represent the genotypes:
- Ax is for axial flower (dominant)
- AxC is for constricted pod (recessive)
- In is for inflated pod (dominant)
- Te is for terminal flower (recessive)
Based on the given numbers, we can construct the Punnett square:
| Ax In | Ax In |
------------|-----------|------------|
Ax In | Ax In | Ax In |
--------------|-----------|------------|
Ax In | Ax In | Ax In |
--------------|-----------|------------|
From the Punnett square, we can see that all of the offspring have genotype Ax In, indicating that the parents are homozygous dominant for both traits. This genotype can be represented as Ax In/Ax In.
To check the explanation, we can perform a test cross. A test cross involves crossing the unknown genotype (Ax In/Ax In) with the recessive homozygous genotype (AxC Te/AxC Te) and observing the offspring. If the unknown genotype is homozygous dominant, the offspring will all show the dominant phenotype (Ax In). On the other hand, if the unknown genotype is heterozygous, we would expect a 1:1 ratio of dominant and recessive phenotypes.
By performing the test cross and analyzing the offspring, we can confirm if the genotype assumed for the parents is correct.
To determine the most probable genotype for the two parents, we need to analyze the offspring's phenotypic ratios and use that information to deduce their genotypes.
Given the offspring ratios:
- 20 with axial flowers and inflated pods
- 7 with axial flowers and constricted pods
- 5 with terminal flowers and inflated pods
We can start by determining the genotypes of each of these phenotypes. Let's assign a lowercase letter, 'a,' to represent the gene for axial flowers and an uppercase letter, 'I,' to represent the gene for inflated pods. Similarly, let's assign another lowercase letter, 'c,' to represent the gene for constricted pods.
From the given data, we can infer that:
- The offspring with axial flowers and inflated pods could be either AAII or AAIi.
- The offspring with axial flowers and constricted pods would have the genotype AaIi.
- The offspring with terminal flowers and inflated pods would have the genotype AAIi.
Now, let's make a Punnett square to determine the possible genotypes of the parents:
| Aa | Ai | aa
------------------------------------------------------
Aa | AaAa | AaAi | aaAa | aaAi
------------------------------------------------------
Ai | AaAi | AaII | aaAi | aaII
Based on the given data, we can make the following conclusions:
- 20 offspring have axial flowers and inflated pods, which can be either AAII or AAIi. Since there are more offspring with this phenotype, it's more likely that both parents have at least one dominant allele for inflated pods (I).
- 7 offspring have axial flowers and constricted pods, which have the genotype AaIi. This means that at least one parent must have the genotype Aa for axial flowers.
- 5 offspring have terminal flowers and inflated pods, which have the genotype AAIi. This means that at least one parent must have the genotype AI for terminal flowers.
So, combining these conclusions, the most probable genotype for the two parents is AaAI × AaII. This possibility fulfills all the given data.
To check this explanation, you can create a new Punnett square using the proposed genotypes (AaAI × AaII) and see if it aligns with the observed offspring phenotypes. If the Punnett square accurately produces the same ratio of offspring, it supports the explanation.