CHAPTER 3 - BIOPSYCHOLOGY
The Big Question
- nature vs nurture
- are we products of our genes or our environment?
- neonate is not a tabula rasa (a blank slate)
- traits are carried by 60-100,000 genes
Genetics - The Basics
- chromossomes: long strings of genetic material (DNA)
- genes: sequences of DNA that control traits
- allele: a variation of a gene
- genome: all genes together
- genotype: underlying genetic code
- phenotype: how to genetic code is manifested
Determinants vs Predispositions
- heritability: a statistic that measures how much variation in a trait is accounted
for by genetics
- estimates apply narrowly (because testing has many control variables)
- across groups, not to individuals (hard to make predictions)
- most traits can be modified by the environment
- some genes determine an absolute result (blue eyes, brown hair, etc)
- others are merely predispositions - greater likelihood of something (addiction,
Alzheimer’s, etc)
Multiple Births
- fertilization of multiple ova -> fraternal twins
- splitting of one fertilized egg -> monozygotic twins
* adoption and twin studies look at heritability vs environment
Genetics can influence...
- physiological traits
- intelligence (fast processing gene)
- personality
- can elicit environmental stimuli
- parents who see that their child likes sports will introduce more sports
into their environment, leading to a cyclical process of improvement
Gene-Environment Interaction
- degree of bidirectional interaction between genes and environment
- we are a combination of our genetics and our environment
- range of reaction: genes determine boundaries; environment
determines where in the possibilities we will fit
, - example: “smart” genes + studying = higher intelligence
- another way to phrase it: how much of our potential we will
reach
- genetic-environmental correlation: both genes and env. interact
bidirectionally; they affect each other simultaneously
- epigenics: studies how the same genotype can result in different
phenotypes
- studies show that, in general, a good environment can reduce a
negative predisposition
- adoptees with mothers with schizophrenia -> mental disturbance
levels with different environments
“Quality of life genetics”
- already exists
- “model” egg donors -> optimizing beauty
- high-achiever sperm banks -> optimizing intelligence
- genetic testing and harvesting of fertilized eggs for Alzheimer’s and
selectively deaf
Real Case of Genetic Editing
- Dr. He Jiankui, from China
- edited the genes of two babies to make them resistant to HIV
- received heavy backlash from the scientific community
Nervous System - Basics
Glial Cells
- scaffolding for neurons, line them up with each other
- insulate and mediate neuronal responses
- transport nutrients and waste
Neurons
Structure
- semipermeable membrane: small, non electrically-charged particles
pass through
- soma: cell body, where nucleus is located
- dentrites: branches that extend from the soma, receive input
- axon: long extension, send input
- terminal buttons: located at the end of axon
- synaptic vesicles and neurotransmitters: where and what transmits the
chemical messages through the nervous system (to other neurons)
- myelin sheath: formed by glial cells on the axon, insulate and increase
transmission speed
The Big Question
- nature vs nurture
- are we products of our genes or our environment?
- neonate is not a tabula rasa (a blank slate)
- traits are carried by 60-100,000 genes
Genetics - The Basics
- chromossomes: long strings of genetic material (DNA)
- genes: sequences of DNA that control traits
- allele: a variation of a gene
- genome: all genes together
- genotype: underlying genetic code
- phenotype: how to genetic code is manifested
Determinants vs Predispositions
- heritability: a statistic that measures how much variation in a trait is accounted
for by genetics
- estimates apply narrowly (because testing has many control variables)
- across groups, not to individuals (hard to make predictions)
- most traits can be modified by the environment
- some genes determine an absolute result (blue eyes, brown hair, etc)
- others are merely predispositions - greater likelihood of something (addiction,
Alzheimer’s, etc)
Multiple Births
- fertilization of multiple ova -> fraternal twins
- splitting of one fertilized egg -> monozygotic twins
* adoption and twin studies look at heritability vs environment
Genetics can influence...
- physiological traits
- intelligence (fast processing gene)
- personality
- can elicit environmental stimuli
- parents who see that their child likes sports will introduce more sports
into their environment, leading to a cyclical process of improvement
Gene-Environment Interaction
- degree of bidirectional interaction between genes and environment
- we are a combination of our genetics and our environment
- range of reaction: genes determine boundaries; environment
determines where in the possibilities we will fit
, - example: “smart” genes + studying = higher intelligence
- another way to phrase it: how much of our potential we will
reach
- genetic-environmental correlation: both genes and env. interact
bidirectionally; they affect each other simultaneously
- epigenics: studies how the same genotype can result in different
phenotypes
- studies show that, in general, a good environment can reduce a
negative predisposition
- adoptees with mothers with schizophrenia -> mental disturbance
levels with different environments
“Quality of life genetics”
- already exists
- “model” egg donors -> optimizing beauty
- high-achiever sperm banks -> optimizing intelligence
- genetic testing and harvesting of fertilized eggs for Alzheimer’s and
selectively deaf
Real Case of Genetic Editing
- Dr. He Jiankui, from China
- edited the genes of two babies to make them resistant to HIV
- received heavy backlash from the scientific community
Nervous System - Basics
Glial Cells
- scaffolding for neurons, line them up with each other
- insulate and mediate neuronal responses
- transport nutrients and waste
Neurons
Structure
- semipermeable membrane: small, non electrically-charged particles
pass through
- soma: cell body, where nucleus is located
- dentrites: branches that extend from the soma, receive input
- axon: long extension, send input
- terminal buttons: located at the end of axon
- synaptic vesicles and neurotransmitters: where and what transmits the
chemical messages through the nervous system (to other neurons)
- myelin sheath: formed by glial cells on the axon, insulate and increase
transmission speed
