Hardy-Weinberg
What does p² represent?
The frequency of the homozygous dominant genotype.
What’s a frameshift?
A mutation caused by insertion or deletion of nucleotides not in multiples of three, altering the reading frame.
What happens in anaphase?
Sister chromatids (mitosis) or homologous chromosomes (meiosis I) are pulled apart.
Who discovered them?
Barbara McClintock.
Define genotype.
The genetic makeup of an organism (e.g., AA, Aa, aa).
One assumption of Hardy-Weinberg equilibrium?
No natural selection, no mutation, random mating, no gene flow, and large population size.
Define point mutation.
A change affecting a single nucleotide base.
What’s nondisjunction?
Failure of chromosomes to separate properly during cell division.
What’s a transposon?
A mobile DNA element that can move within the genome.
What is a haplotype?
A group of genes or alleles inherited together from a single parent.
What breaks Hardy-Weinberg equilibrium?
Factors like selection, mutation, non-random mating, genetic drift, or migration.
What does EMS do?
Ethylmethanesulfonate causes G→A transitions by alkylating guanine.
What are univalents?
Unpaired chromosomes during meiosis, can lead to segregation errors.
Retro vs DNA transposon?
Retrotransposons use RNA intermediates and reverse transcription; DNA transposons move via a "cut and paste" mechanism.
Define nonsense mutation.
A mutation that introduces a premature stop codon.
Use the equation if q² = 0.16
q = 0.4; p = 0.6; heterozygous (2pq) = 0.48 or 48%.
How do UV rays mutate DNA?
Cause thymine dimers that distort DNA structure.
Result of trisomy?
A gamete or zygote with one extra chromosome (e.g., Down syndrome with trisomy 21).
% of genome they occupy?
Around 45% in humans.
What’s “identical by descent”?
Alleles inherited from a common ancestor without recombination.
How is H-W used in real studies?
To test whether a population is evolving at a particular gene locus.
Mutation vs. DNA damage?
DNA damage is a structural abnormality; mutation is a permanent change in the sequence.
Bivalents vs. trivalents?
Bivalents are pairs of homologous chromosomes; trivalents are three homologous chromosomes attempting to pair, often due to chromosomal abnormality.
Difference: humans vs plants?
Plants often have more active DNA transposons; humans mostly have inactive retrotransposons.
Define allotetraploid.
An organism with two sets of chromosomes from two different species.