In some bees, thin stripes $(S)$ are dominant over thick stripes $(s)$, and black eyes $(B)$ are dominant over gray eyes $(b)$. Complete a dihybrid cross for parents with the genotypes SsBB and ssBb and determine the likelihood of offspring with the genotype ssBB.
Answer (2)
Count the number of offspring with the genotype ss BB in the Punnett square: 4.
Determine the total number of offspring: 16.
Calculate the probability of offspring with genotype ss BB : 16 4 .
Simplify the fraction: 4 1 .
Explanation
Analyze the problem We are given a Punnett square for the cross of two bees with genotypes S s BB and ss B b . Our goal is to determine the probability that an offspring will have the genotype ss BB .
Count the number of offspring with genotype ssBB The Punnett square shows the genotypes of all possible offspring from the cross. We need to count how many offspring have the genotype ss BB . Looking at the Punnett square, we can see that there are four offspring with the genotype ss BB .
Determine the total number of offspring The total number of possible offspring is 16, as shown in the Punnett square (4 rows x 4 columns = 16).
Calculate the probability To find the probability of an offspring having the genotype ss BB , we divide the number of ss BB offspring by the total number of offspring: 16 4 = 4 1 Therefore, the probability of an offspring having the genotype ss BB is 4 1 .
State the final answer The likelihood of offspring with the genotype ss BB is 4 1 .
Examples
In genetics, Punnett squares are used to predict the genotypes and phenotypes of offspring. For example, if you are breeding plants and want to know the likelihood of getting a specific trait (like disease resistance), you can use a Punnett square to analyze the possible genetic combinations. This helps breeders make informed decisions about which plants to cross to achieve desired traits in their crops. The same principles apply to animal breeding or even understanding inherited traits in humans.
The probability of offspring with the genotype ss BB from the cross of S s BB and ss B b is 4 1 . This is calculated using a Punnett square that shows 4 occurrences of ss BB out of a total of 16 possible outcomes. Therefore, 4 1 is the final answer.
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