46. White fur (W) is dominant to black fur (w) in a species. Two individuals of Ww phenotype are crossed. What is the probability of the offspring having a Ww genotype?
Answer: B
The probability of the offspring having a Ww genotype is 50%.
When two individuals with the Ww genotype are crossed, the potential genotypes of their offspring can be determined using a Punnett square. The resulting genotypic ratio shows that there is a 50% chance of the offspring being Ww.
A) 25%
This option is incorrect because, in a cross between two Ww individuals, the Punnett square indicates that the probability of obtaining Ww offspring is higher than 25%. The correct distribution of genotypes is 1 WW, 2 Ww, and 1 ww, leading to a much higher chance for Ww.
B) 50%
This option is correct as it accurately represents the probability of producing offspring with the Ww genotype when crossing two Ww individuals. The Punnett square shows that out of four possible outcomes, two outcomes (Ww) result in this genotype, confirming a 50% probability.
C) 75%
This option is incorrect because it overestimates the probability of obtaining a Ww genotype. The Punnett square results in a total of four combinations, only two of which are Ww, indicating that 75% is not supported by the genetic ratio.
D) 100%
This option is incorrect as it suggests that all offspring from the cross will have the Ww genotype. The genetic combination from the Ww x Ww cross shows that there are also other genotypes possible (WW and ww), making it impossible for the probability to be 100%.
Conclusion
The correct answer is 50% because the cross between two Ww individuals yields a genotype ratio indicating that half of the offspring are expected to be Ww. All other options fail to accurately represent the results derived from the genetic cross, either by underestimating or overestimating the likelihood of the Ww genotype.