Chapter 2 Flashcards
Notion of a Paradigm
*Paradigm (Thomas Kuhn)
= a conceptual framework or approach within which a scientist works
*A set of basic assumptions
*A general perspective
*An approach to conceptualizing the study of a subject and how to interpret data
Genetic Paradigm
- Almost all behavior is heritable to some degree
- Genes do not operate in isolation from the environment: The environment shapes how our genes are expresses & Our genes also shape our environments
- Relationship between genes and environment is bidirectional: Nature via nurture (Ridley, 2003)
Nature via nurture
*researchers are learning how environmental influences, such as stress, relationships, and culture (the nurture part), shape which of our genes are turned on or off and how our genes (the nature part) influence our bodies and brain. We know that without genes, a behavior might not be possible. But without the environment, genes could not express themselves and thus contribute to the behavior.
Genes
: Carriers of genetic information (DNA)
Gene expression:
process by which the instructions in our DNA are converted into a functional product, such as a protein.
many functions of proteins, including influencing the expression of other genes
Humans have how many genes?
20-25K genes.
function of proteins
many functions of proteins, including influencing the expression of other genes
Polygenic
-no one gene that will make someone depressed (more than 2 or 3, really is more like thousands)
example!
Heritability
- Extent to which variability in behavior is due to genetic factors
- Heritability estimate ranges from 0.00 to 1.00
- Group, rather than individual, indicator
the higher the number the _____ the heritability
the higher the number the greater the heritability
Shared environment
-Events and experiences that family members have in common
*e.g., Income level, child-rearing practices, parent’s marital status and quality
(families have same shared environmental factors)
Nonshared environment
- Events and experiences that are distinct to each family member
e. g., relationships with friends, events unique to the person - May explain sibling differences
Behavior Genetics
= Study of the degree to which genes and environmental factors influence behavior
- Studies estimate heritability of a psychological disorder but don’t explain how genes work.
e. g., twin/adoption studies
Genotype
-is it observable
Genetic makeup inherited by an individual
Unobservable
(what is in the DNA)
Phenotype
- Expressed genetic material
- Observable behavioral characteristics
- Depends on interaction of genotype and environment
Molecular Genetics
- Identifies genes and their functions
* Identifies differences between people in the sequence of their genes and in the structure of their genes
Alleles
Different forms of the same gene
Polymorphism
= Difference in DNA sequence on a gene occurring in a population
(example is the colorful birds?)
Current Molecular Genetics Research focuses on : 2 things
*identifying differences between people in the sequence of their genes and in the structure of their genes.
SNPs (Single Nucleotide Polymorphisms)
= Difference between people in a single nucleotide in the DNA SEQUENCE of a particular gene
(has the same number but different sequence)
-falls under current molecular genetics research
CNVs (Copy Number Variations)
= Abnormal copy of one or more sections of DNA within the gene(s)
- Differences in STRUCTURE of gene
- Additions or deletions in DNA within genes
- falls under current molecular genetics research
GWAS (Genome-Wide Association Studies)
- Key method to examine SNPs and CNVs
- Isolate differences in the sequence of genes between people who have a psychological disorder and people who do not
(looking at a lot of people: comparing the affected vs unaffected individuals)
Gene-environment interaction
A person’s sensitivity to an environmental event is influenced by genes and vice-versa
Genes do not exert their effects in isolation so we need to consider _____
Gene-Environment Interactions!