What is the expected genotypic ratio in the F2 generation of a monohybrid cross?
Practice Questions
Q1
What is the expected genotypic ratio in the F2 generation of a monohybrid cross?
1:2:1
3:1
9:3:3:1
1:1
Questions & Step-by-Step Solutions
What is the expected genotypic ratio in the F2 generation of a monohybrid cross?
Step 1: Understand what a monohybrid cross is. It involves crossing two organisms that differ in one trait.
Step 2: Identify the parental generation (P generation) and their genotypes. For example, one parent might be homozygous dominant (AA) and the other homozygous recessive (aa).
Step 3: The first generation (F1) will all be heterozygous (Aa) because they inherit one allele from each parent.
Step 4: When the F1 generation (Aa) is crossed with itself (Aa), we set up a Punnett square to predict the offspring.
Step 5: Fill in the Punnett square. You will have four boxes representing the possible combinations of alleles: AA, Aa, Aa, and aa.
Step 6: Count the genotypes from the Punnett square. You will find 1 AA (homozygous dominant), 2 Aa (heterozygous), and 1 aa (homozygous recessive).
Step 7: Write the genotypic ratio based on your counts: 1 AA : 2 Aa : 1 aa.
