Question

Experiment 3: Plant Genetics: Inheritance of Two Genes

Plants provide a useful model for studying inheritance. In this experiment, you will use Wisconsin Fast Plant™ seeds to evaluate how two genes are passed from parents to their progeny. Anthocyanin is a purple pigment that produces a visible marking in many plants. It is best observed when plants are four to seven days old. The presence of the anthocyaninless gene (anl) in Wisconsin Fast Plants™ regulates expression of the pigment. Homozygous recessive plants (anl/anl) express no purple pigment because the gene is suppressed. Heterozygous plants (anl/ANL) and homozygous dominant plants (ANL/ANL), do produce a purple stem phenotype.

Procedure

Use the permanent marker to label the petri dishes for each of the seed types: P₁, P₂, F₁, and F₂.

Place each filter paper disk under a gently stream of tap water to dampen. Be careful not to soak the filter paper!

Remove the lids from each of the four petri dishes. Place one piece of filter paper in the bottom half of each dish.

Pour the seeds from each envelope into the corresponding labeled petri dish.

Replace the lid atop the dish. Place each dish in a resealable bag, and zip the bag shut.

Position the petri dishes under a fluorescent light (approximately 8 - 10 cm from the light source is optimal).

Check the filter paper disks daily for approximately one week to ensure that it remains damp. In detail, record any observations, predictions, and results in the Data section (located at the end of this procedure). Determine the best way to quantify the differences in phenotypes observed (stem and leaf color).

Record final phenotypes of each type of plant.

Answer 1

Phenotypes:
F1 – Green Leaves, Purple Stem
F2 – Green Leaves, Purple Stem
P1 – Yellow Leaves, Green Stem
P2 – Green Leaves, Green Stem