Part 1: Three Point Testcross Bench
| Offspring class (v cv ct) | Observed | Expected |
|---|
Simplified model for learning. The female (heterozygous for vermilion eyes v, crossveinless wings cv and cut wings ct) is testcrossed with a v cv ct / v cv ct male; fly males do not cross over. In each of her meioses, a chiasma forms in a region with probability 2 × (distance ÷ 100), at most one per region, between a random pair of non-sister chromatids, and one of the four chromatids becomes the egg. Interference lowers the chance of a chiasma in both regions to (1 − I) times the independent value. Distances are limited to 25 cM per region so this simple model stays valid. Timing is sped up.
Worksheet: analyze your own data
Run a testcross first. Then classify each offspring class, find the middle gene, and compute the distances, the coefficient of coincidence and interference from your counts. Distances to one decimal place in cM; CoC and I to two decimal places.
| Class | Count | Your classification |
|---|
Part 2: Mapping Problem Trainer
Problems are randomly generated, so every one is new. Distances in cM (you may type cM or %), to one decimal place unless asked otherwise. Counts and genotypes are made up for practice.
Part 3: Terms and Classes Match
Your job
Drag a card onto a box, or tap a card and then tap the box's name. Cards are buttons, so Tab and Enter work too.
Part 4: Mapping in the Real World
Families, plants and data are made up for teaching and simplified. For learning only, not medical advice or genetic counseling.
Wrong picks are fine here. Each one tells you why.