Lesson 10 of 12
🧬 Genetics & Heredity
What You'll Learn
- DNA → genes → traits
- dominant vs recessive alleles
- Punnett squares
- probability of traits
Key Concepts
DNA is found in the nucleus and contains genes — instructions for building proteins and traits. Genes come in versions called alleles.
Dominant alleles (capital letters) mask recessive alleles (lowercase). A Punnett square predicts offspring genotype probabilities when you know parent alleles.
Example: Tt × Tt cross gives TT(25%), Tt(50%), tt(25%) — so 75% chance of showing the dominant trait.
🔬 Virtual Lab
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Quick Check
In a Tt × Tt cross, what fraction of offspring will show the dominant trait?
Where is DNA found inside a eukaryotic cell?