What is the phenotype ratio for a monohybrid cross of two heterozygous individuals?

Understanding Monohybrid Cross and Phenotype Ratio

In genetics, a monohybrid cross is a breeding experiment between two individuals that are heterozygous for a single gene of interest. This means that each parent has two different alleles for the gene, with one dominant allele and one recessive allele.

When two heterozygous individuals are crossed, the offspring inherit one allele from each parent, resulting in a genotype with two different alleles. The phenotype, or physical characteristics, of the offspring are determined by the combination of alleles they inherit.

Phenotype Ratio in Monohybrid Cross

The phenotype ratio for a monohybrid cross of two heterozygous individuals is 3:1. This ratio indicates that the dominant allele would show up in 3 individuals, while the recessive allele would show up in 1 individual.

For example, if we cross two heterozygous individuals with the genotypes Aa (dominant allele) and Aa (dominant allele), the offspring would have the following genotype and phenotype ratio:

• AA (dominant phenotype): 1 individual
• Aa (dominant phenotype): 2 individuals
• aa (recessive phenotype): 1 individual

This ratio demonstrates the Mendelian principle of dominant and recessive alleles in determining the phenotype of offspring in a monohybrid cross.