Genetics, Epigenetics, and Environment - Vocabulary Flashcards

A set of vocabulary flashcards covering key terms from the notes on genetics, epigenetics, environment, and twin studies.

epigenetics

The study of heritable changes in gene expression that do not involve changes to the DNA sequence (e.g., DNA methylation, histone remodeling).

histone

Protein around which DNA wraps to form chromatin; modifications affect gene accessibility.

chromatin

Complex of DNA and proteins that packages genetic material in the nucleus and regulates gene access.

chromatin remodeling

Changes in chromatin structure that make genes more or less accessible for transcription.

DNA methylation

Addition of methyl groups to DNA; typically alters and often represses gene expression.

histone acetylation

Addition of acetyl groups to histone tails; generally loosens chromatin and increases gene expression.

methyl group

Chemical group (-CH3) added during methylation of DNA.

acetyl group

Chemical group added during histone acetylation (facilitates looser chromatin).

gene

A DNA sequence that codes for a protein or other functional product.

allele

A variant form of a gene; different flavors that can be inherited.

genotype

An individual's genetic make-up, i.e., the set of alleles they carry.

phenotype

Observable traits of an individual resulting from the genotype and environment.

chromosome

A DNA-protein structure that carries genes and units of heredity.

SNP (single nucleotide polymorphism)

A single base-pair variation in DNA; common form of genetic variation.

PKU (phenylketonuria)

An inherited metabolic disorder caused by deficient enzyme; can cause developmental problems if untreated; diet-managed.

heredity/heritability

Proportion of variation in a trait across a population that is due to genetic differences; ranges from 0 to 1 and applies to groups, not individuals.

monozygotic twins

Identical twins from a single fertilized egg that splits; share nearly all DNA.

dizygotic twins

Fraternal twins from two different fertilized eggs; share about half of their DNA.

twin studies

Research design comparing monozygotic and dizygotic twins to estimate genetic vs environmental contributions.

selective breeding

Mating organisms for desired traits to demonstrate genetic influence on behavior or physiology.

maze-bright

Rats bred for high maze-learning ability; tend to explore and learn quickly.

maze-dull

Rats bred for poor maze-learning ability; tend to perform poorly and may be more cautious.

enriched environment

Environment with increased stimuli (toys, wheels, tunnels) that enhances learning and development.

impoverished environment

Minimal environment with limited stimulation and resources.

tabula rasa

Latin for blank slate; view that individuals are born without built-in content and are shaped by environment.

natural selection

Darwinian mechanism by which environment pressures cause differential survival and reproduction.

Mendelian genetics

Genetics describing discrete genes and simple inheritance patterns (dominant/recessive, segregation).

gene–environment interaction

Concept that genetic predispositions and environmental factors interact to shape traits; cannot predict individuals precisely.

identical strangers

Ethical case of identical twins raised apart to study nature vs. nurture; highlighted limits and insights of twin research.