Answer :
To solve this problem, we need to determine the probability of getting a homozygous recessive offspring when crossing a heterozygous "WW" with a homozygous dominant "WW". Here's the step-by-step reasoning:
1. Identify the Genotypes:
We have two organisms being crossed:
- Heterozygous "WW"
- Homozygous Dominant "WW"
2. Setting Up the Punnett Square:
Since both parents have the genotype "WW", we can set up a simple Punnett square to see the possible offspring.
| | W | W |
|-------|---|---|
| W | WW | WW |
| W | WW | WW |
3. Analyze the Punnett Square:
In the Punnett square, all possible combinations of alleles result in "WW".
4. Determine the Types of Offspring:
- All offspring from this cross will have the genotype "WW". This is because each parent contributes a "W", and there are no "N" alleles in the mix at all.
5. Probability of Homozygous Recessive Offspring:
Homozygous recessive offspring would need to have the genotype "NN" (assuming "N" is the recessive allele), but since both parents provide only "W", it is impossible to get an "NN" genotype.
6. Conclusion:
Therefore, the probability of having a homozygous recessive offspring (genotype "NN") is 0. There are no alleles that could combine to give a recessive "NN" genotype in this cross.
1. Identify the Genotypes:
We have two organisms being crossed:
- Heterozygous "WW"
- Homozygous Dominant "WW"
2. Setting Up the Punnett Square:
Since both parents have the genotype "WW", we can set up a simple Punnett square to see the possible offspring.
| | W | W |
|-------|---|---|
| W | WW | WW |
| W | WW | WW |
3. Analyze the Punnett Square:
In the Punnett square, all possible combinations of alleles result in "WW".
4. Determine the Types of Offspring:
- All offspring from this cross will have the genotype "WW". This is because each parent contributes a "W", and there are no "N" alleles in the mix at all.
5. Probability of Homozygous Recessive Offspring:
Homozygous recessive offspring would need to have the genotype "NN" (assuming "N" is the recessive allele), but since both parents provide only "W", it is impossible to get an "NN" genotype.
6. Conclusion:
Therefore, the probability of having a homozygous recessive offspring (genotype "NN") is 0. There are no alleles that could combine to give a recessive "NN" genotype in this cross.