AP BIOLOGY

Detailed explanation-1: -Punnett Square makes use of a grid and letters. In particular, capital letters represent dominant alleles and lower case letters to recessive alleles. With this tool, the known genotypes of each parent are shown to help predict the possible genotypes of their offspring.

Detailed explanation-2: -A Punnet square shows the genes (represented by letters) in the parents’ gametes along the top and left-hand side of a square and the possible gene combinations in the offspring, within the square. A completed Punnett square gives the probable outcome of a given cross.

Detailed explanation-3: -What do the letters in each box of the Punnett square tell you? The possible combinations of alleles in offspring based on parents’ genetic makeup.

Detailed explanation-4: -A Punnett square shows the probability of an offspring with a given genotype resulting from a cross. It does not show actual offspring. For example, the Punnett square in Figure 3 shows that there is a 25% chance that a homozygous recessive offspring will result from the cross Aa x Aa.

Detailed explanation-5: -When discussing genotype, biologists use uppercase letters to stand for dominant alleles and lowercase letters to stand for recessive alleles. With eye color, for instance, “B” stands for a brown allele and “b” stands for a blue allele.