ITP Topic 1 Genes and evolution

Psychological science

is the study through research, of mind, brain, and behaviour

The Mind

refers to mental activity and includes the memories, thoughts, feelings, and perceptual experiences (sense) we have while we interact with the world

Behaviour

describes the totality of observable human (or animal) actions

Amiable skepticism

being open to new ideas but carefully considering the evidence

Genome

The complete set of DNA of an organism/species.

it is the blueprint that provides detailed instructions for everything in the organism. the genome provides the options, and the environment determines which option is taken

The Cell

Cell→nucleus→46 chromosomes→coiled strands of DNA→the DNA has double helix shape→DNA made up of complementary chains of adenine, thymine, guanine, and cytosine

Gene

Segment of the DNA

What does a gene do?

governs the cells functioning by providing instructions for making proteins

protein

made up of polypeptides, which are chains of amino acids linked together by peptide bonds

gene expression

whether a particular gene is turned on or off

How is gene expression possible

Methylation, which is when a methyl group is added to DNA. This does not remove a gene but changes how accessible and active it will be; often reducing gene expression

genotype vs phenotype

an organisms internal genetic code vs the observable physical expression of that code (always changing); which is determined by genotypeXenvironment

Polygenic trait

is a characteristic controlled by the combined action of two or more genes

Each gene is paired with another gene

Yes, the pairs are located at corresponding positions on pairs of chromosomes

Allele

is one specific variant of a gene which can be either dominant or recessive

Homozygote vs heterozygote

Homozygote means the alleles on the locus are the same while heterozygote means the alleles on the locus are different

A specific trait or behaviour is determined by what?

The interaction between the environment and gene: one gene pair or multiple gene pairs which is polygenetic inheritance

Heredity

This is passing on characteristics from parents to offspring by means of genes

Heritability

Its a statistical estimate of the extent to which variation of a particular trait within a population is due to genetics

Charles Darwins evolution theory

Believes the genome is shared by evolution over the years; that we are descended from a small set of shared ancestors and have merged over time through the process of evolution

What’s the key mechanism of evolution?

Natural selection

There’s three conditions needed for natural selection (all must be met)

1. Variation among individuals of a population

2. Individuals with a certain trait survive and reproduce at higher rates than others

3. the trait associated with this advantage is passed from parents to offspring

Evidence for modern evolutionary theory (natural selection)

1. fossil records show: gradual changes along heritage lines, splits in heritage lines, and transition forms between different species

2. the resemblance between genomes of various organisms

3. the existence of pseudogenes→nonfunctioning; probably functioned in our ancestors

4. distribution of species across the world

Ways genetic expression can be modified

MAOA gene, epigenetic, genetic modification, optogenetics

MAOA (gene)

its the gene that controls levels of MAO, which is an enzyme that breaks down monoamine neurotransmitters like dopamine, serotonin, and norepinephrine

Two variants of MAOA

one is associated with higher MAO levels, one with lower levels. boys with Low-MAOA variant were more susceptible to the effects of childhood maltreatment so they were more likely to be convicted of violent crime

Epigenetics

looks at how environment affects genetic expression. we know that various environmental exposures don’t later DNA, but do alter gene expression. The EPIGENETIC TAGS can be passed down