PPE EXAM 3 STUDY GUIDE Ch 6 Genetics and Personality 1 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 DNA 2 Know the difference between a phenotype and a genotype Genotype an organism s genetic info Phenotype an organism s observable characteristics 3 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 differences 6 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 not Drinking Thought to be related to Sensation seeking Extraversion Neuroticism Drinking 36 56 Alcoholism 50 71 10 Know that any phenotype variance not accounted for by genetics is accounted for by the environment e g if height is 90 heritable 10 of the variance is due to the environment 11 Know the difference between shared and non shared environments Shared environment home Non shared environment peers 12 Be able to define and recognize
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