Which tool is used to predict offspring genotypes from parental alleles?

• A. Pedigree
• B. Karyotype
• C. Punnett square
• D. Gel electrophoresis

Answer: (C)

Predicting offspring genotypes from parental alleles relies on the Punnett square. This tool lays out the alleles each parent can pass as gametes along two sides of a grid and then fills each cell by combining one allele from each parent. The result shows all possible genotypes and how often each would occur. For example, crossing two heterozygotes (Aa x Aa) gives 1 AA, 2 Aa, and 1 aa, meaning a 25%/50%/25% distribution for the genotypes. This visual makes Mendelian inheritance concrete, showing how dominant and recessive alleles influence offspring genotypes. The method works for more complex crosses too, though the grid grows larger. It’s important to note that this approach assumes alleles segregate and assort independently and that there aren’t additional complicating factors. Other tools serve different purposes: pedigrees trace patterns across generations, karyotypes examine chromosome number and structure, and gel electrophoresis separates DNA fragments, but they don’t directly predict the exact genotype combinations offspring will receive.