1. Genetics and Psychology
How much do genes decide our behavior?
Pages 72-74

2. Genes: Our Code for life
Ms. Martin shares
98% with
And 99.9% with

3. All cells contain DNA

4. Chromosomes and Genes Each cell has 46 chromosomes = 23 pairs
Genes give instructions to perform a certain function
Two of this set are X and Y (the sex chromosomes) and the other 22 pairs guide the expression of other traits.

6. Dominant vs Recessive genes
2 recessive genes = recessive trait
1 dominant + 1 recessive = dominant
2 dominant = dominant

7. Behavior Geneticists
Ask questions about the extent that genetics plays on our differences
Heritability – statistical estimate of how much behavior is due to genes. Max value is 1.0

8. Twin Studies
Identical Twins- develop from a single fertilized egg that splits in two, creating two genetically identical organisms
Fraternal Twins - develop from separate eggs
genetically no closer than brothers and sisters, but they share the fetal environment

9. Twins and heritability studies
Bouchard – studied 100 twins raised apart and their IQ scores
Those raised apart = coefficient of .69 on IQ test
Those raised together = .88
Criticized = adopted parents have particular environment

10. Molecular Genetics
Looks at genes that can specifically cause disorders
Gender determined by 23rd chromosome pair
Men = XY – means some recessive characteristics from mother not blocked (color blindness)
Women = XX

11. Chromosomal Disorders
Turner’s Syndrome
Single X on 23rd pair
Shortness, webbed necks, sterility

12. Chromosomal Disorders
Klinefelter’s syndrome – XXY pattern
Males – less testosterone, weaker body, possible infertility
Down’s Syndrome
Extra chromosome on the 21st pair

13. Geneticists can now test for some disorders in Utero
Down’s syndrome
Tay-Sachs disease (death to nerve cells mental/physical deform. onset
Spina Bifida (one of most common in U.S. 1/1000 births – spinal)
Looking for an increase in a protein or hormone in early pregnancy