1. THE MEANING OF HERITABILITY (H) The Genetics of Difference THE MEANING OF HERITABILITY (H)

2. IMPORTANT FACTS ABOUT HERITABILITY – THE PROPORTION OF THE TOTAL VARIANCE IN A TRAIT THAT IS ATTRIBUTABLE TO GENETIC VARIATION WITHIN A GROUP MAX VALUE IS 1.0 HEIGHT HAS A HIGH H

3. APPLIES ONLY TO A PARTICULAR GROUP IN A PARTICULAR ENVIRONMENT DOES NOT APPLY TO INDIVIDUALS, ONLY VARIATIONS WITHIN GROUPS EVEN HIGHLY HERITABLE TRAITS CAN BE MODIFIED BY ENVIRONMENT (MALNUTRITION AND WT./HT.) http://www.youtube.com/watch?v=bsdHDTIP PU8 http://www.youtube.com/watch?v=bsdHDTIP PU8

4. COMPUTING HERITABILITY ADOPTION STUDIES – SHARE ½ GENETIC MAKE UP, BUT NOT ENVIRONMENT – CORRELATIONAL COMPARISON BETWEEN TRAITS OF PARENTS AND KIDS – ATTEMPT TO SEPARATE ENVIRONMENTAL FROM GENETIC FACTORS

6. TWIN STUDIES – COMPARE SAME SEX FRATERNAL TWINS WITH GROUPS OF IDENTICAL TWINS – ID TWINS MORE ALIKE EQUALS HIGH H – TO AVOID SOCIAL BIAS, ID TWINS THAT WERE SEPARATED ARE BEST (see BOUCHARD & LYKKEN)