Answer :
To solve this question, we need to look at two genetic crosses:
1. Cross between a heterozygous male Ww and a homozygous recessive female ww:
- The male has genotype Ww, meaning he has one dominant allele (W) and one recessive allele (w).
- The female has genotype ww, meaning she has two recessive alleles.
We can use a Punnett square to determine the possible genotypes of the offspring.
- The male can pass on either a W or a w allele.
- The female can only pass on a w allele since she is homozygous recessive.
Possible combinations are:
- W from male and w from female gives Ww (heterozygous)
- w from male and w from female gives ww (homozygous recessive)
Filling out the Punnett square gives us:
- Ww, Ww, ww, ww
There are 4 possible outcomes:
- 2 of them are Ww (heterozygous)
- 2 of them are ww (homozygous recessive)
So, the probability of producing a heterozygous offspring (Ww) is 2 out of 4, which equals 50%.
2. Cross between a homozygous dominant WW with another homozygous dominant WW:
- Both parents have genotype WW, meaning they have two dominant alleles.
Since both can only pass on a W allele because they are homozygous dominant, all offspring will have genotype WW.
There are no ww (homozygous recessive) offspring possible in this cross.
Therefore, the probability of having a homozygous recessive offspring is 0%.
In summary, for the first cross, there's a 50% chance of producing a heterozygous (Ww) offspring, and for the second cross, there is a 0% probability of having a homozygous recessive (ww) offspring.
1. Cross between a heterozygous male Ww and a homozygous recessive female ww:
- The male has genotype Ww, meaning he has one dominant allele (W) and one recessive allele (w).
- The female has genotype ww, meaning she has two recessive alleles.
We can use a Punnett square to determine the possible genotypes of the offspring.
- The male can pass on either a W or a w allele.
- The female can only pass on a w allele since she is homozygous recessive.
Possible combinations are:
- W from male and w from female gives Ww (heterozygous)
- w from male and w from female gives ww (homozygous recessive)
Filling out the Punnett square gives us:
- Ww, Ww, ww, ww
There are 4 possible outcomes:
- 2 of them are Ww (heterozygous)
- 2 of them are ww (homozygous recessive)
So, the probability of producing a heterozygous offspring (Ww) is 2 out of 4, which equals 50%.
2. Cross between a homozygous dominant WW with another homozygous dominant WW:
- Both parents have genotype WW, meaning they have two dominant alleles.
Since both can only pass on a W allele because they are homozygous dominant, all offspring will have genotype WW.
There are no ww (homozygous recessive) offspring possible in this cross.
Therefore, the probability of having a homozygous recessive offspring is 0%.
In summary, for the first cross, there's a 50% chance of producing a heterozygous (Ww) offspring, and for the second cross, there is a 0% probability of having a homozygous recessive (ww) offspring.
