• Twin Studies: Looking at identical and non-identical twins to see how traits are passed down.
• Family Studies: Examining how traits appear in different family members.
• Adoption Studies: Looking at adopted kids and their biological vs. adoptive families.

Think of it like a puzzle; by putting all these pieces together, we can see how genes affect us!

• Twin Studies Evidence: 40-50% heritability of depression.
• Family Studies: First-degree relatives (like your parents or siblings) are 2-3 times more likely to be depressed.

Imagine having a 50% chance of loving pineapple on pizza because your twin does. That's genetics!

What's in the Mix?: Phenotype (what you can see) is influenced by

• A = Genetic Inheritance (37%): Like inheriting your grandma's eye color.
• C = Shared/Common Environment (0%): Growing up in the same house with the same rules.
• E = Individual Environment (63%): Your unique experiences, like being the star of the school play!

It's like baking a cake: 37% flour (genes), 0% sugar (shared environment), and 63% chocolate (individual environment). Yum!