Which term involves a grid method to calculate offspring genotypes by crossing two individuals?

• A. Punnett Square
• B. Pedigree
• C. Karyotype
• D. Genome

Answer: (A)

The grid method for predicting offspring genotypes is called a Punnett square. It visualizes all possible allele combinations from two parents by laying out each parent’s gametes on the top and side of a grid and filling in each cell with the resulting offspring genotype. This shows every possible genetic combo a pair can produce and helps you read off genotype and phenotype probabilities—for a simple single-gene cross, you often get a 1:2:1 genotype ratio and, depending on dominance, a corresponding phenotype ratio.

For example, crossing two heterozygous individuals (both Aa) using a Punnett square yields the genotypes AA, Aa, Aa, and aa, illustrating the 1:2:1 ratio. Pedigrees, karyotypes, and genomes describe different genetic concepts or tools: pedigrees map inheritance through families; karyotypes show chromosome number and structure; and a genome is the complete set of an organism’s genetic material.