Behavioral Genetics, Evolution, and Epigenetics (Video Notes)

Vocabulary flashcards covering key terms from nature–nurture, genetic research designs, evolution in psychology, mating strategies, and epigenetics.

Nature–Nurture question

The ongoing debate about how genes (nature) and environment/experience (nurture) shape traits and behavior, including implications for responsibility and moral judgment.

Adoption studies

Research design comparing adoptees to biological and adoptive parents to separate genetic influence from environmental influence.

Monozygotic (MZ) twins

Identical twins sharing nearly 100% of their DNA.

Dizygotic (DZ) twins

Fraternal twins sharing about 50% of their DNA.

Heritability

A population-level index (0–1) of how much trait variation is due to genetic differences.

Quantitative genetics

A field analyzing genetic similarities among relatives to estimate heritability and genetic influence on traits.

Behavioral genetics

The study of how genes and environment interact to shape behavior.

Epigenetics

Stable, reversible changes in gene expression without altering the DNA sequence, regulated by chemical marks.

Epigenome

The full set of chemical marks that regulate gene expression in a cell.

Chromatin

DNA wrapped around histone proteins; its structure affects gene expression.

Nucleosome

The basic unit of chromatin: DNA wrapped around a histone core.

DNA methylation

Addition of methyl groups to CpG sites, often silencing genes, mediated by DNMT enzymes.

Promoters

Start regions of genes; when open/accessible, transcription can occur.

Enhancers

Regulatory DNA sequences that increase gene transcription; can be far from or close to the gene.

Histone acetylation

Addition of acetyl groups by HATs, opening chromatin and boosting gene expression.

Histone deacetylation

Removal of acetyl groups by HDACs, closing chromatin and reducing expression.

Histone code

Combination of histone modifications that regulate cell-specific gene expression programs.

Phenotypic plasticity (epigenetic tuning)

Early-life experiences shape brain development and stress reactivity via epigenetic marks, influencing emotion and cognition.

GR promoter methylation (NR3C1)

Methylation of the glucocorticoid receptor promoter linked to early adversity and altered stress responses.

Maternal care epigenetics in rats

Low maternal care increases DNA methylation and histone modifications at GR promoter in hippocampus, raising stress hormones; partly reversible with interventions.

NR3C1/GR methylation biomarker

Promoter methylation of the glucocorticoid receptor gene linked to early adversity and stress reactivity.

Gene Selection Theory

Genes are units of heredity that guide behavior to increase their own replication via individual and inclusive fitness.

Individual fitness

An organism’s survival and reproductive success.

Inclusive fitness

Genetic success of an individual achieved by helping relatives share genes.

Sexual Strategies Theory (SST)

Humans evolved multiple mating strategies (short-term and long-term) that vary with context, parental investment, and mate value.

Parental investment asymmetry

Women bear higher obligatory investment (e.g., pregnancy) and tend to be choosier; men typically have lower immediate costs.

Mutual mate choice

In humans, both sexes influence mate selection; long-term desirables include kindness, intelligence, dependability.

Error Management Theory (EMT)

Minds evolve biases under uncertainty to minimize costly errors when payoffs are asymmetric.

Visual Descent Illusion

An EMT-supported example showing perceptual biases related to risk and height perception.