Question

Be able to explain and write two ways in which the F2 progeny may beanalyzed further to reveal their genotypes in experiments such as Mendel's.

Answer 1

Two ways to analyze F2 progeny genotypes in Mendelian experiments are using a Punnett square to predict the expected genotypic and phenotypic ratios, and performing a test cross to reveal whether F2 individuals are homozygous dominant or heterozygous.

Step-by-step explanation:

When analyzing F2 progeny in experiments like Mendel's, it is critical to reveal the underlying genotypes that determine their phenotypes. Two ways to further analyze the F2 generation are as follows:

1. Punnett Square Analysis: By using a Punnett square, we can predict the genotypes of the F2 progeny based on the genetic cross of F1 individuals. This tool allows us to determine the expected genotypic and phenotypic ratios and compare them with observed data.
2. Test Cross: Performing a test cross involves crossing the F2 individuals with a homozygous recessive individual for the traits under consideration. This cross can help to determine whether the F2 individual is homozygous dominant or heterozygous by examining the phenotypes of the resulting progeny.

In Mendel's classic experiments, he crossed plants that differed in traits such as seed color and form. For instance, plants with yellow or green seeds and smooth or wrinkled seeds were crossed, resulting in the F2 generation exhibiting a 9:3:3:1 phenotypic ratio for these two traits.

For a concrete example, when analyzing data such as observing 2706 tall/inflated, 930 tall/constricted, 888 dwarf/inflated, and 300 dwarf/constricted plants amongst the F2 progeny, a researcher would first reduce these numbers to a ratio to see if they align with the expected 9:3:3:1 phenotypic ratio, which supports Mendelian laws of inheritance.