Monohybrid Crosses: Inheritance of single genes

General question format: Features to look for Example: Mendel crosses a heterozygous tall pea plant with a short pea plant. If tall is dominant to short, what is the genotype & phenotype ratio of the F1 generation? Genotype of individual 1 Genotype of individual 2 Explains dominance What you’re looking for

Solution Use a let statement to show which traits are dominant and recessive. Let T = tall, t = short Use the first letter of the dominant trait! Capital = dominant, lowercase = recessive

2. Determine the genotypes of the parents. Individual 1: heterozygous tall: Tt Individual 2: short: tt Means 2 different alleles! Recessive in this case, so it must be 2 lowercase letters

3. Draw a Punnett Square, as you learned in the handout and fill it in

4. Answer the question: Phenotype ratio is 2 Tall : 2 short Genotype ratio is 2 Tt : 2 tt Remember: it means physical appearance Remember: it means letters/alleles