Select the correct answer from each drop-down menu. If a heterozygous male with the genotype Ww is mated with a homozygous recessive female of genotype ww, there is a chance that $\square$ of the offspring will be heterozygous.
| | w | w |
|---|----|----|
| w | Ww | ww |
| w | Ww | ww |
If the heterozygous, WW, is crossed with a homozygous dominant, WW, then the probability of having a homozygous recessive offspring is
| | W | w |
|---|----|----|
| w | WW | Ww |
| W | WW | Ww |
Answer (2)
2 1 and 0
Explanation
Analyze the first Punnett square Let's analyze the first Punnett square. The possible offspring genotypes are Ww and ww. There are two Ww offspring out of a total of four offspring. Therefore, the probability of heterozygous offspring (Ww) is 4 2 = 2 1 .
Analyze the second Punnett square Now let's analyze the second Punnett square. The possible offspring genotypes are WW and Ww. There are zero ww offspring out of a total of four offspring. Therefore, the probability of homozygous recessive offspring (ww) is 4 0 = 0 .
Final Answer Therefore, the probability that the offspring will be heterozygous in the first cross is 2 1 , and the probability of having a homozygous recessive offspring in the second cross is 0.
Examples
Understanding the probability of offspring genotypes is crucial in genetics. For example, if a certain disease is recessive, knowing the genotypes of the parents allows us to predict the likelihood of their children inheriting the disease. This knowledge can inform family planning and genetic counseling.
The probability of offspring being heterozygous (Ww) from a cross between Ww and ww is 2 1 . The probability of offspring being homozygous recessive (ww) from a cross between Ww and WW is 0. Therefore, the final answers are 2 1 and 0, respectively.
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