Use the Punnett square below to answer the question.
YY or Yy = yellow flowers
yy = white flowers
GG or Gg = green seeds
gg = black seeds
What percent of offspring are dihybrids?
A. $25 \%$
B. $6.3 \%$
C. $18.7 \%$
Answer (2)
Count the number of dihybrid offspring (YyGg) in the Punnett square: 4.
Determine the total number of offspring: 16.
Calculate the percentage of dihybrid offspring: 16 4 × 100 = 25 .
The percentage of offspring that are dihybrids is 25% .
Explanation
Understand the problem We are given a Punnett square that represents the offspring genotypes from a dihybrid cross. We need to determine the percentage of offspring that are dihybrids. A dihybrid offspring has the genotype YyGg.
Count the dihybrid offspring Now, let's count the number of offspring with the YyGg genotype in the Punnett square.
Looking at the Punnett square, we can identify the cells with the YyGg genotype. There are four such cells.
Determine the total number of offspring The total number of offspring represented in the Punnett square is 16 (4 rows x 4 columns).
Calculate the percentage of dihybrid offspring To find the percentage of dihybrid offspring, we divide the number of YyGg offspring by the total number of offspring and multiply by 100: 16 4 × 100 = 25 Therefore, 25% of the offspring are dihybrids.
State the final answer The percentage of offspring that are dihybrids (YyGg) is 25%.
Examples
In genetics, understanding the probability of specific traits appearing in offspring is crucial for breeders and researchers. For example, a plant breeder might use a Punnett square to predict the likelihood of obtaining plants with desired traits, such as yellow flowers and green seeds, when crossing two parent plants with known genotypes. This helps in making informed decisions about which crosses are most likely to yield the desired results, saving time and resources in the breeding process.
The percentage of dihybrid offspring in the Punnett square is 25%, calculated by dividing the number of dihybrid offspring by the total number of offspring and multiplying by 100. The correct answer choice is A. 25%.
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