PPE EXAM 3 STUDY GUIDECh. 6 Genetics and Personality1) Understand the hierarchy of the genome. (Chromosomes are made up of what? Genes are made of what? Etc.)Human Genome: sequence of the entire human genome; completed in 2003; just because we know about it does not mean we know what functions each part performs- We are actually not that complex- fruit flies are more complex than us (and have more variability- we are remarkably alike to one another, we are not very diverse). Our complexity comes from our triggers of our DNA, not the DNA itself. - Genome (23 chromosomes) Chromosomes (thousands of genes) Genes DNA2) Know the difference between a phenotype and a genotype.- Genotype: an organism’s genetic info- Phenotype: an organism’s observable characteristics3) Know the goals of behavioral genetics.- To determine: - What % of trait difference is due to genetics and what & is due to environ?- How do genes and environ interact?- What environmental effects are important? (e.g., parents, teachers, peers)4) Be able to define and describe heritability and environmentality. - Heritability: examining a trait within a population, and examining what percentage of the variance seen within that population is due to genetics. - How much an individual difference is explained by genetics- Enironmentality: Proportion of observed variance explained by environmental factors (studies find intelligence to be half genes, half environ)-Shared and Non-shared- Shared Environment: in family environ, features of the environ shared by siblings (ex: number of books in home)- Non-shared Environment: in family environment, features of the environ that differ across siblings (ex: different friends, different teachers)- How much of an individual difference is due to environment- For most personality traits, the environ has major influence primarily in the form of non-shared variable because the shared usually has little impact- Environ/Heritability Relationship: inversely proportional to one another (both add up to equal 100%). Surprisingly, some things we think are clear-cut are actually not at all (like gender- sometimes people’s genes tell a different story). 5) Be able to recognize examples of common misconceptions about heritability.- Heritability:- Proportions of phenotypic variance that is attributable to genotypic variance- Group level stat; NOT A PRECISE STATISTIC- Tells nothing of individuals amount of variability across large groups of people that can be attributed to genetics- Heritability is not about the individual…. It is about trends seen in populations!- It is a changing statistic- environments vary over time- It is an estimate, especially since the statistics are from a sample, not whole population- Evidence of heritability does exist: MZ twins are more similar than DZ twins- Cannot be applied to a single person- A single individual’s height, for example, is not 90% due to his/her genes- It is more accurate to say that the variation between people in height is 90% due to genetic differences6) Be able to list, define, and describe the four methods used in behavioral genetics.- Twin Studies: Heritability is based on these types of studies. Twin studies correspond to eugenics. Estimate heritability by gauging if identical twins, which share 100% of genes are more similar than fraternal twins, who share only 50% of their genes. Based on similar genetics and environ. The theory is that they have equal environments, but that is not always the case; and the assumption that they are representative of whole populations may or may not be true- Family Studies: Closer you are biologically, the more you should see a certain trait being shown. Like could give a survey within a family and see if the cousins are like the siblings; Problem: Families share genes and environment so family studies are never definitive- Selective Breeding: Unethical for humans! But we can use it for both dogs and monkeys. The limit is that we cannot apply it to actual people!- Adoption Studies: Least reliable study; studies of biological siblings reared apart gives you the genetic basis interacting with different environments. The best in this case is also twins, and even better identical twins reared apart (exact DNA replication). BUT…selective placement issue (tend to be placed with people that look like them), and hard to get scores from parent, kid, and biological parent, and may or may not be representative still. - Representativeness: are adopted children and adoptive/genetic parents representative of the general population?- Selective Placement: Does a child’s adoptive parents tend to be similar to his or her genetic parents?7) Know how each of the four methods used in behavioral genetics can provide information about the heritability of traits (e.g. How can studying twins help scientists to determine the heritability of extraversion?)SEE QUESTION 6 ^^^8) Know the difference between monozygotic and dizygotic twins. - MZ: share a single fertilized egg (a single zygote=MZ); share 100% of genes- DZ: come from two separately fertilized eggs (two zygotes = DZ); share 50%9) Know the major findings of behavioral genetics that were discussed in class.- Personality Traits: 30-50% heritability; 50-70% Environmentality - Attitudes and Preferences; Sexual orientation has current evidence that suggests that genes provide modest and indirect influence (via childhood gender non conformity) on adult sexual orientation (heritability of about 40%) Heritability of traditionalism is high at 60%. Heritability in beliefs in God is LOW. - Drinking and Smoking: Stability of drinking and smoking is stable over time and show evidence of heritability; Personality traits manifested include sensation seeking, extroversion, and neuroticism. *** Big Five has a heritability of about 20-45% via temperament - The Big Five- Extraversion (40-60% heritable)- Neuroticism (30-54% heritable)- Sexual Orientation: controversial and developing area- Genes modest and indirect influence on adult sexual orientation (20-67% heritability)Attitudes and Preferences: - A lot of variance in heritability- Some show high heritability (traditionalism 34-63%)- Others show low/no heritability (belief in God)- Researchers don’t agree on exactly what makes an attitude heritable or notDrinking: - Thought to be related to - Sensation-seeking- Extraversion- Neuroticism - Drinking (36-56%)- Alcoholism (50-71%)10) Know that any phenotype variance not
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