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Genetics and Psychology

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Presentation on theme: "Genetics and Psychology"— Presentation transcript:

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

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