Genetics

Question 1

human genome

Answer 1

• refers to complete set of genes that an organism possess
• genome contains 30k-80k genes on 23 pairs of chromosomes
• small nb of genes = different for different individuals

Question 2

Human Genome project

Answer 2

• designed to sequence the entire human genome

Question 3

controversy

Answer 3

• behavioural geneticists attempt to determine the degree to which individual differences are caused by genetic and environmental differences
• concerns:
  1. ideological concerns: no room for change; suggests plasticity is not present
  2. concerns about renewed interest in eugenics

Question 4

temperament vs trait

Question 5

goals of behavioural geneticists

Answer 5

1. % of individual differences ina trait that can be attributed to genetic differences/envrionmental differences
2. ways in which genes and environment interact and correlate with each other to produce individual differences
3. where in the “environment” environmental effects exist

Question 6

T or F? Any trait that we still have has served an adaptive purpose

Answer 6

true

Question 7

genotypic variance

Answer 7

refers to individual differences in the total collection of genes possessed by each person

Question 8

phenotypic variance

Answer 8

refers to observed individual differences, such as height, weight, personality, etc.

Question 9

heritability

Answer 9

proportion of phenotypic variance that is attributable to genetic variance

Question 10

environmentality

Answer 10

proportion of phenotypic variance that is attributable to environmental variance

Question 11

epigenetics

Answer 11

• effect of environment on gene expression
• silent gene becomes expressed; expressed gene becomes silent

Question 12

heritability misconceptions

Answer 12

• cannot be applied to a single individual
• not constant
• not a precise statistic

Question 13

nature vs nurture?

Answer 13

• no such debate at the individual level
• influences of genes and environment is only relevant for the discussion of group level variation

Question 14

diathesis-stress model

Question 15

selective breeding

Answer 15

• occurs by identifying the dogs that
  possess the desired characteristic and having them mate only with other dogs that also possess the characteristic
• Dog breeders have been successful precisely because many of the qualities they wish specific dog breeds to have are moderately to highly heritable

Question 16

traditional behavioural genetic methods

Answer 16

• selective breeding studies
• family studies
• twin studies
• adoption studies

Question 17

traditional behavioural genetic methods - selective breeding studies: advantages vs disadvantages

Answer 17

advantages:
- can infer heritability if selective breeding works
disadvantages:
- are unethical to conduct on humans

Question 18

traditional behavioural genetic methods - family studies: advantages vs disadvantages

Answer 18

advantages:
- provide heritability estimates
disadvantages:
- violate equal environments assumption

Question 19

traditional behavioural genetic methods - twin studies: advantages vs disadvantages

Answer 19

advantages:
- provide both heritability and
environmentality estimates
disadvantages:
- sometimes violate equal environments
assumption

Question 20

traditional behavioural genetic methods - adoption studies: advantages vs disadvantages

Answer 20

advantages:
- provide both heritability and
environmentality estimates
- get around the problem of equal environments
assumption
disadvantages:
- adopted kids might not be representative of population
- problem of selective placement

Question 21

selective placement

Answer 21

if adopted children are placed with
adoptive parents who are similar to their birth parents, then this may inflate the correlations between the adopted children and their adoptive parents

Question 22

do MZ twins seem to be functionally more similar to each other than the environments experienced by the DZ twin?

Answer 22

No

Question 23

twin studies

Answer 23

if a trait is highly heritable
- family members with greater genetic relatedness should be ore similar to one another on the trait than family members are less closely related
problem:
- members of a family who share the same environment influence the process

Question 24

twin studies: assumptions

Answer 24

1. equal environment assumption
   - because parents provide both genes and environments to their children, and may provide more similar environments for identical than for fraternal twins, there is a potential compromise of the equal environments assumption
2. representativeness

Question 25

adoption studies

Answer 25

genetic parents provide none of the environmental influences on their children, thus unconfounding genetic and environmental causes

Question 26

contrast effect

Answer 26

- children try to be different from siblings

Question 27

birth order effects

Answer 27

- each child experiences parents different

Question 28

Falconer's formula: calculting heritability

Answer 28

2 = 2(rmz - rdz) refer to p. 168 of textbook

Question 29

major statistical findings in personality

Answer 29

- heritability estimates for major personality traits of about 0.20-0.45 - some studies suggest as high as 48% across all 5 traits - stability of these traits

Question 30

major findings: attitude and preference

Answer 30

wide variance in heitability of attitudes

Question 31

major findings: drinking and smoking

Answer 31

- behavioural manifestations of personality traits (sensation seeking, extraversion, neuroticism) - drinking alcohol and smoking cigs are stable over time - both show evidence of heritability

Question 32

shared vs nonshared environmental influences

Answer 32

personality characteristics show heritability in 30-50% range - hence showing substantial degree of environmentalism (50-70% range)

Question 33

shared vs nonshared environmental influences: types of environmental influences

Answer 33

1. shared - in family environement, features of the environment shared by siblings - e.g. nb of books in home 2. nonshared - in family environment, features of the environment that differ across siblings - e.g. teachers, friends

Question 34

genotype-environment interaction

Answer 34

- differential response of individuals with different genotypes to the same environments (e.g. task performance of introverts vs extraverts in quiet vs noisy conditions) - differential exposure of individuals with different genotypes to different environments - genotype-environemnt correlations can be + or (passive, reactive, active)

Question 35

passive genotype-environment correlation

Answer 35

- parents provide both genes and environemnt to children, yet children do nothing to obtain that environment - e.g. child's verbal ability and nb of books at home

Question 36

reactive genotype-environment correlation

Answer 36

- parents (or others) respond to children differently depending on child's genotype - e.g. baby's liking for cuddling and mother's cuddling

Question 37

active genotype-environment correlation

Answer 37

- person with particular genotypes seek out a particular environment - high sensation seekers expose themselves to risky environments