BIOL 1040 The DNA Revolution EXAM 2

GWAS

A method to identify genetic variants associated with traits by scanning the genome.

SNP

A variation at a SINGLE DNA base pair among individuals.

Linkage Disequilibrium

A statistical correlation between alleles at different loci

GWAS hit

A SNP that shows statistically significant association with a phenotype.

Manhattan plot

A graph showing the strength of association between SNPs and traits across the genome.

Odds Ratio

A measure of how much a genetic variant increases or decreases the odds of a trait or disease.

Recombination

The exchange of genetic material between chromosomes during meiosis

Genotype

An individual's genetic makeup at specific loci.

Phenotype

An observable trait or characteristic influenced by genotype and environment.

Polygenic trait

A trait influenced by many genes

Polygenic score

A composite measure of genetic predisposition based on many SNPs across the genome.

Missing heritability

The gap between heritability estimates from twin studies and those from GWAS.

Sample size effect

Larger sample sizes increase statistical power and confidence in GWAS associations.

Statistical significance

A measure indicating that an observed association is unlikely due to chance.

Genome neighborhood effect

Genes located near each other tend to be inherited together and may show correlated effects.

Genotype-by-environment interaction

Genetic effects vary depending on the environmental context in which they are expressed.

UK Biobank

A large-scale genomic and phenotypic dataset from over 500000 individuals that have had their genome sequenced.

Rare variant

Genetic variants with low population frequency that may have large individual effects.

Common variant

Genetic variants with high population frequency that typically have small effects.

Recombination hotspot

A region of the genome where crossover events occur more frequently.

Linkage equilibrium

Alleles at different loci are inherited independently.

Linkage disequilibrium

Alleles at different loci co-occur more frequently than expected by chance.

Chromosome crossover

The exchange of genetic material between homologous chromosomes during meiosis.

Genetic architecture

The overall pattern of genetic contributions to a trait

Trait heritability

The proportion of phenotypic variance in a population explained by genetic factors.

Twin study heritability

Heritability estimated by comparing monozygotic and dizygotic twin similarities.

GWAS heritability

Heritability estimated from SNPs that reach genome-wide significance.

Population design heritability

Heritability estimated from genetic similarity between unrelated individuals.

Educational attainment GWAS

A study linking genetic variation to differences in education levels.

Genetic determinism

The idea that genes alone determine traits — often oversimplified and controversial.

Genetic essentialism

A flawed belief that genetic traits are fixed and define identity or ability or that one gene can control one trait.

Genetic lottery

Metaphor for random inheritance of genetic traits — used in Harden’s book.

Population genetics

The study of genetic variation within and between populations.

Out-of-Africa model

Modern humans originated in Africa and spread globally

Neanderthal and Denisovan

Modern humans interbred with these archaic hominins during migration and we share in some cases a significant portion of our genome with them.

Minor allele frequency

The frequency of the less common allele in a population.

Effect size

The magnitude of a genetic variant’s influence on a trait.

Copy number variant

A type of genetic variation involving duplication or deletion of DNA segments.

Protein-truncating variant

A mutation that shortens a protein

Genetic association

A statistical link between a genetic variant and a trait.

Causal variant

A genetic variant that directly influences a trait or disease.

GWAS catalog

A database of published GWAS hits across traits and diseases.

Genomic sequencing

Determining the complete DNA sequence of an organism’s genome.

Trait mapping

Identifying genomic regions associated with specific traits.

Disease liability

A measure of genetic predisposition to disease.

Case-control study

A GWAS design comparing individuals with and without a trait or disease.

Genetic correlation

A measure of shared genetic influence between traits.

Risk allele

An allele associated with increased risk of a trait or disease.

Protective allele

An allele associated with decreased risk of a trait or disease.

Genetic diversity

Variation in DNA sequences among individuals or populations.

Genetic ancestry

The origin of an individual’s DNA based on population history.

Environmental modifier

A factor that alters the effect of a genetic variant.

Social environment

Contextual factors like racism or inequality that interact with genetic expression.

Systemic racism

A societal structure that disadvantages certain groups

Educational attainment

Often studied in GWAS due to its correlation with economic outcomes.

IQ test

A bad intelligence test but good standardized measure of problem-solving ability

Modifiability

The degree to which gene expression can be changed by environmental factors.

Genetic studies of personality

GWAS increasingly used to study traits like neuroticism and extraversion.

Ethical caution in GWAS

Important to avoid misinterpretation and misuse of genetic findings in social contexts.

Trait variance

The total variation in a trait across a population

Genetic predisposition

A higher likelihood of developing a trait based on genetic makeup.

Genomic data

Information derived from sequencing or genotyping an individual’s DNA.

Phenotypic spectrum

Traits often exist on a continuum rather than binary categories.

Germline

Germlines are cells and structures that form eggs and sperm.  

Somatic

Any cell of a living organism other than the reproductive cells.

Soma

Are cells that are a machine that work to keep the germline going

Polygenic Prediction

Estimate of an individual's genetic predisposition to complex diseases by combining the effects of many common genetic variants (SNPs).

Evolutionary Trees

Reconstructions of history that can show mating patterns based on what we know on sequenced data.