week2_lect3_genetics.pdf

Biological & Environmental Foundations Week 2, Lecture 3, January 19, 2024 1 Reminders: ▰ Science Reflection Due Monday January 22 ▻ 48 hour grace period for submitting assignments 2 Genetic Foundations of Development ▰ Cell: ▻ Contains 23 matching pairs of chromosomes ▰ Chromosomes: ▻ Holds basic u...

Biological & Environmental Foundations Week 2, Lecture 3, January 19, 2024 1 Reminders: ▰ Science Reflection Due Monday January 22 ▻ 48 hour grace period for submitting assignments 2 Genetic Foundations of Development ▰ Cell: ▻ Contains 23 matching pairs of chromosomes ▰ Chromosomes: ▻ Holds basic unit of heredity (genes) ▰ Genes: ▻ Composed of deoxyribonucleic acid (DNA) 3 Genotype vs. Phenotype ▰ Genotype: sum of all genes a person inherits ▰ Phenotype: The set of observable characteristics of an individual ▰ Physical ▰ Neural ▰ Behavioural Genotype Phenotype 4 Genotype vs. Phenotype 1) There is significant genetic variation for most phenotypes 2) Many genes affect one phenotype (Most have small effects) 3) Pleiotropy: one gene can influence multiple phenotypes 5 Early Experience (The Environment) Early Experience Abuse Family strife Emotional neglect Harsh discipline Phenotypes Individual differences Physical Diabetes Heart disease Obesity Neural Response to stress Brain development Behavioural Depression/Anxiety 6 Genetics and the Environment ▰ Genes vs. Environment ▰ Genes + Environment ▰ Gene-Environment Interplay 7 Genotypes correlate with Phenotypes ▰ Genes do not determine, control or cause behaviour. ▰ Rather, they influence the probability that behavioural differences will be expressed in a given environment. 8 Behavioural Genetics ▰ how genes and experience combine to influence human characteristics ▰ Heritability: extent to which variation of a trait or behavioural is due to genetic influences ▰ What does it mean for something to be 50% heritable? ▻ 50% of variation in a behaviour in a population can be predicted by variability between genes 9 Methods of Behavioural Genetics: ▻ Selective breeding: ▻ Modifying genes of animals ▻ Family studies (twins, adoption) Monozygotic (MZ) Dizygotic (DZ) 10 Behavioural Genetics 1) Genes correlate with the environment 2) Gene x Environment interactions are pervasive. 3) Epigenetics: Environment affects gene expression. 11 Gene Environment Correlations Three types of Gene Environment Correlations: ▻ Passive ▻ Active ▻ Evocative ▰ Prevalence of type changes across development (Plomin et al., 1977; Scar & Mcarthy 1983) 12 Gene Environment Correlations ▰ Passive GE-Correlation ▻ An individuals genes will correlate with their early environment. ▰ More prominent early in development 13 Gene Environment Correlations ▰ Evocative GE-Correlation ▻ An individual’s genes influences the way that others respond to them. ▰ Present throughout development 14 Gene Environment Correlations ▰ Active GE-Correlation ▻ An individual’s genes influences their selective attention to different aspects of the environment. ▰ More prominent later in development 15 What type of gene - environment correlation? Ex1: When Keisha was a teenager, people described her as “moody”. She had times when she would get very sad for a weeks at a time. Now, at age 28, Keisha has had her first child, Marcus. Keisha is struggling to manager her mood - she feels stressed all the time, and she has negative thoughts about herself and motherhood. Because things are so hard for her, Keisha does not smile at Marcus much and gets easily frustrated when he cries. The way that Keisha is acting toward Marcus could make it more likely that he develop a mood or behavior problem later on in childhood Ex2: Marcus, age 14, is very bright. His parents were, too - his father started a successful small business, and his mother is a doctor. Marcus loves learning and opted to take honors classes when he started high school. Compared to most of his classmates, Marcus is learning about more advanced topics in his honors classes. Marcus’ choice to take honors classes have the effect of increasing his IQ Ex3. Marcus, age 18, is not only naturally gifted but also worked very hard in high school. HIs hard work got him to college where he is majoring in psychology. Marcus continues to work hard in his college class and has made a reputation for himself in the psychology department. Professors have seen how bright Marcus is and how hard he works. They give him extra attention in class and a couple of them have asked him to work in their research labs. Ex. 4 Harry and Holly met at a motorcycle convention. They are both very outgoing, adventurous people. After dating for a while, Harry and Holly had a baby girl - Natalie. Natalie, now age 7, is a lot like her parents in that she is “intense” and can be hard to handle. Because she is so adventurous and curious, she often gets into things that she’s not supposed to. Harry and Holly are always scolding and disciplining Natalie to keep her in line. Come up with your own examples! Passive My example Genetic Trait In Parents Parents are shy - pass on shy genes on to child Parents Create Environment to match Genes Parents do not go out a lot or have people over Outcome for Child Child doesn’t get practice with people is more shy Your example Evocative My example Child’s actions according to their genes Shy child doesn’t go up to other kids, doesn’t talk when greeted Reactions by people changes environment to match genes Other people leave child alone. Don’t invite them over to play as much Outcome for Child Child doesn’t get practice with people is more shy Your example Active My example Your example Child’s genetically based talent or trait Child is shy Child chooses environment to match genes Child chooses classes, major or job that doesn’t involve interacting with people Outcome for Child Child doesn’t get practice with people is more shy