Punnett Squares
📋 What it is
A Punnett square predicts the chances of offspring traits from the parents’ genes.
🗣️ Coach says
A Punnett square is a simple grid that predicts trait odds. You put each parent’s gene versions (alleles) on the sides and fill the boxes to see the possible combinations in their offspring — like rolling dice for genes. It shows PROBABILITIES, not guarantees.
🧠 Memory hook
Punnett square = a grid predicting trait ODDS from parents’ genes.
😂 Giggle
Why was the recessive allele so quiet at parties?
It could never express itself when the dominant one was around!
😲 Whoa!
A single Punnett square can predict that two brown-eyed parents might still have a blue-eyed child — if both carry a hidden recessive gene.
✅ Quick check: What does a Punnett square tell you — a guarantee or a probability?
Say your answer out loud first — then reveal.
A probability — it shows the CHANCES of each trait combination in offspring, not a certain outcome.
Punnett squares give the odds of inherited traits, not guarantees.
🧪 Try it! (2 minutes)
Draw a 2×2 grid. Put “B” and “b” on top, “B” and “b” on the side. Fill it — how many boxes show at least one B?