1. Monohybrid Crosses: Inheritance of single genes

2. 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

3. 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

4. 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

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

6. 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