Genetic Processes and Population Genetics

Flashcards covering key concepts from the lecture on DNA transcription, translation, types of mutations (point and chromosomal), the forces of evolution, and the Hardy-Weinberg Principle in population genetics.

DNA Transcription

The process of taking DNA strands and creating an RNA transcript.

DNA Translation

The process of taking an RNA transcript and creating a sequence of amino acids, which forms a protein.

Amino Acids

The building blocks that are translated from RNA to form proteins.

Protein Synthesis

The overall process involving transcription and translation, where DNA information is used to build proteins.

Start Codon (AUG)

A specific sequence in mRNA (typically AUG) that signals the beginning of translation.

Stop Codon

A specific sequence in mRNA that signals the end of protein synthesis during translation.

Point Mutation

A change in a single nucleotide base within a DNA sequence.

Silent Mutation

A type of point mutation where a nucleotide change occurs but does not alter the amino acid sequence of the resulting protein, having no phenotypic outcome at the protein level.

Missense Mutation

A type of point mutation where a nucleotide change leads to the creation of a different amino acid in the protein sequence.

Nonsense Mutation

A type of point mutation where a nucleotide change results in a premature stop codon, leading to a shortened, often non-functional protein.

Frameshift Mutation

A type of point mutation involving the insertion or deletion of one or more nucleotides (not in multiples of three) that shifts the reading frame, leading to a completely different sequence of amino acids in the protein.

Mutation Impact (Deleterious)

A harmful effect of a mutation, often reducing an organism's fitness; most mutations are neutral or mildly deleterious.

Chromosomal Mutations

Large-scale changes in the structure or number of chromosomes.

Inversion (Chromosomal)

A type of chromosomal mutation where a segment of a chromosome breaks off, flips in orientation, and then reattaches.

Translocation (Chromosomal)

A type of chromosomal mutation where a section of one chromosome breaks off and becomes attached to a different, non-homologous chromosome.

Deletion (Chromosomal)

A type of chromosomal mutation where a chunk of a chromosome, potentially including several genes, is lost.

Duplication (Chromosomal)

A type of chromosomal mutation where a chunk of a chromosome, including genes, is copied, resulting in extra copies of that segment.

Karyotype

A visual representation of an individual's complete set of chromosomes, used to identify large-scale chromosomal mutations like fusions or deletions.

Evolution (Population Genetics)

A change in the characteristics of populations through time, specifically defined as a change in allele frequencies over time.

Allele Frequency

The proportion or relative abundance of a specific allele (e.g., A or a) within a population's gene pool.

Population Genetics

A field of study focused on how allele frequencies change in populations over time, leading to evolution.

Natural Selection

A process driving evolution where alleles that improve an organism's survival or reproductive success increase in frequency over time.

Genetic Drift

Changes in allele frequencies within a population due to random sampling, especially significant in finite (small) populations.

Gene Flow

Changes in allele frequencies driven by the movement of individuals (and thus their alleles) between different populations.

Mutation (Evolutionary Force)

A change in the underlying DNA sequence that introduces new alleles into a population and is the ultimate source of all new genetic variation.

Modern Synthesis

An era (early to mid-20th century) where Darwinian evolutionary theory and Mendelian genetics were integrated, establishing the mathematical foundations of population genetics.

Hardy-Weinberg Principle

A mathematical null hypothesis for studying evolutionary processes, predicting genotype and allele frequencies in a population under assumptions of no evolution, random mating, and Mendelian genetics.

Gene Pool

The total collection of all alleles from all gametes within a population in each generation, which are imagined to combine randomly.

Hardy-Weinberg Equation

p² + 2pq + q² = 1, where p² is the frequency of the homozygous dominant genotype, 2pq is the frequency of the heterozygous genotype, and q² is the frequency of the homozygous recessive genotype.

Hardy-Weinberg Equilibrium (HWE)

A state in which allele and genotype frequencies in a population will remain constant from generation to generation in the absence of evolutionary influences.

Predicting Genotype Frequencies (HWE)

Under Hardy-Weinberg Equilibrium, allele frequencies (p and q) can be used to predict genotype frequencies; without HWE, this prediction is not possible.