genetics Flashcards
What is behavioural genetics?
The study of how genetic factors influence individual differences in behaviour and psychological attributes.
What is a genotype?
The unique genetic makeup of an individual.
What is a phenotype?
The observable traits and behaviours resulting from genetic and environmental interactions.
How many chromosomes do humans have?
23 pairs of chromosomes (46 total).
What chromosomes determine biological sex?
XX for females, XY for males.
What is DNA?
Deoxyribonucleic Acid, a molecule that contains genetic instructions.
What are the four nucleotide bases in DNA?
Adenine (A), Thymine (T), Guanine (G), Cytosine (C).
Which DNA bases pair together?
A with T, G with C.
What is a gene?
A segment of DNA that acts as a recipe to make proteins.
What is a codon?
A sequence of three nucleotide bases that codes for an amino acid.
How many amino acids are there in humans?
21 amino acids.
What is an allele?
A version of a gene at a specific locus on a chromosome.
What is heritability?
The proportion of trait variation in a population due to genetic factors.
What does a heritability score of 0.4 mean?
40% of variation in the trait is due to genetics (in the population).
What is Mendelian genetics?
The principles of heredity discovered by Gregor Mendel using pea plants.
What is a dominant allele?
An allele that is expressed even if only one copy is present.
What is a recessive allele?
An allele that is expressed only if two copies are present.
What causes Down’s syndrome?
An extra copy of chromosome 21 (Trisomy 21).
What is phenylketonuria (PKU)?
A recessive disorder where the body can’t process phenylalanine due to a faulty enzyme.
How is PKU treated?
With a special diet that avoids phenylalanine.
What causes colour blindness?
A recessive gene on the X chromosome affecting cone cell development.
Why is colour blindness more common in males?
Males have only one X chromosome, so one recessive gene is enough to express the trait.
What is selective breeding?
Breeding organisms with specific traits to examine genetic influence.
What did Tryon’s maze rat experiment show?
That maze learning ability has a genetic component.
What are monozygotic twins?
Identical twins from one egg, sharing 100% of their genes.
What are dizygotic twins?
Fraternal twins from two eggs, sharing about 50% of their genes.
What are concordance studies?
Studies comparing the presence of traits in twins to assess genetic influence.
What is a Genome-Wide Association Study (GWAS)?
A method to find genetic variations associated with specific traits by scanning genomes.
What is epigenetics?
The study of heritable changes in gene expression not caused by changes in the DNA sequence.
What is DNA methylation?
The addition of a methyl group to DNA, reducing gene expression.
What is histone remodelling?
Changes to the proteins around which DNA is coiled, affecting gene expression.
