What does a Punnett square primarily help predict in a genetic cross?

What does a Punnett square primarily help predict in a genetic cross?

• A. Offspring genotypes and phenotypes
• B. Parental ages
• C. Sibling birth order
• D. Gene expression timing

Answer: (A)

Punnett squares predict offspring genotypes and phenotypes in a genetic cross. By listing the alleles each parent can contribute and combining them, the square shows all possible genotypes of the offspring and, with knowledge of dominance, the corresponding phenotypes. It also conveys the relative likelihood of each outcome, such as a 1:2:1 genotype ratio in a simple heterozygous cross and the resulting phenotypic proportions if one allele is dominant. For example, crossing Aa with Aa yields AA, Aa, Aa, and aa in a 1:2:1 genotypic ratio, which translates to the phenotype distribution depending on dominance. Other options don’t fit because Punnett squares aren’t used to predict parental ages, birth order, or the timing of gene expression; those topics involve development, regulation, and life history factors rather than inherited allele combinations. So its main purpose is to forecast the genetic makeup and visible traits of offspring.

Punnett squares predict offspring genotypes and phenotypes in a genetic cross. By listing the alleles each parent can contribute and combining them, the square shows all possible genotypes of the offspring and, with knowledge of dominance, the corresponding phenotypes. It also conveys the relative likelihood of each outcome, such as a 1:2:1 genotype ratio in a simple heterozygous cross and the resulting phenotypic proportions if one allele is dominant. For example, crossing Aa with Aa yields AA, Aa, Aa, and aa in a 1:2:1 genotypic ratio, which translates to the phenotype distribution depending on dominance. Other options don’t fit because Punnett squares aren’t used to predict parental ages, birth order, or the timing of gene expression; those topics involve development, regulation, and life history factors rather than inherited allele combinations. So its main purpose is to forecast the genetic makeup and visible traits of offspring.