Review Flashcards

Flashcards based on lecture notes on RNA-Based Gene Regulation, Chromosomal Variants, Genomics, and Population Genetics.

mRNA Secondary Structures

RNA molecules that can fold into shapes that regulate gene expression.

Attenuation

Regulation via the terminator sequence in the 5' UTR of the trp operon.

Riboswitches

Located in the 5' UTR of mRNA, bind ligands, and affect transcription/translation.

Aptamer Domain

Part of a Riboswitch that binds the ligand.

Antisense RNA (asRNA)

Long non-coding RNAs complementary to target mRNA, preventing translation.

RNA Interference (RNAi)

A defense against double-stranded RNA viruses.

Dicer

Enzyme that cuts dsRNA into siRNAs or miRNAs.

RISC (RNA-induced silencing complex)

Uses siRNAs/miRNAs to bind complementary mRNA, leading to degradation or translation inhibition.

miRNA (microRNA)

Small, single-stranded RNA that binds imperfectly to mRNA, blocking translation.

siRNA (small interfering RNA)

Derived from the target gene, binds perfectly to mRNA, causing degradation.

RITS (RNA-induced transcriptional silencing)

siRNA that recruits methyltransferase enzymes to methylate DNA for epigenetic silencing.

Long Noncoding RNA (lncRNA)

Transcripts ≥200 nucleotides that regulate gene expression by binding to DNA, RNA, or proteins.

Xist (X-inactive specific transcript)

lncRNA that coats one X chromosome in females, leading to X inactivation.

Lyon hypothesis

Inactivation is random and happens in early development.

Chromosomal Variants

Larger-scale mutations compared to point mutations.

Balanced Chromosomal Variant

No net gain/loss of genetic information.

Unbalanced Chromosomal Variant

Deletion/duplication = gene dosage change.

Duplication

A chromosomal segment is copied and inserted.

Tandem Duplication

Duplication adjacent to the original segment.

Dispersed Duplication

Duplication is located elsewhere on the chromosome or genome.

Copy Number Variants (CNVs)

Variations in the number of copies of a particular DNA sequence in the genome.

Paralogs

Duplicated genes within a species that evolve new functions.

Deletion

Loss of a chromosome segment.

Pseudodominance

When deletion exposes recessive alleles in heterozygotes.

Inversion

A chromosome segment is flipped 180°.

Paracentric Inversion

Inversion that does not include the centromere.

Pericentric Inversion

Inversion that includes the centromere.

Translocation

Movement of a segment to a nonhomologous chromosome.

Reciprocal Translocation

Exchange between chromosomes.

Non-reciprocal Translocation

One-way movement of a chromosome segment.

Robertsonian translocation

Occurs at or near centromeres of acrocentric chromosomes.

Transposable Elements (TEs)

DNA sequences that can change their position within a genome.

DNA Transposons

Cut and paste via transposase.

Retrotransposons

Copy and paste via reverse transcription.

Autopolyploidy

Multiple sets of chromosomes from one species.

Allopolyploidy

Combines chromosome sets from two or more species.

Genomics

Study of genetic material across entire genomes.

Structural Genomics

Focuses on the sequence and arrangement of genes within a genome.

Functional Genomics

Explores how genetic variation influences phenotypic traits.

Comparative Genomics

Compares gene content and structure across species to understand evolutionary changes.

Genome Assembly

The most current version of the entire genome sequence of an organism.

Shotgun Sequencing

DNA is extracted, fragmented, and sequenced.

Gene Annotation

Identifies and describes genes and functional regions in the genome.

Ab Initio Prediction

Uses bioinformatics to search for necessary gene components.

Homology-Based Annotation

Uses known expressed genes or protein domains to predict new gene functions.

SNPs (single nucleotide polymorphisms)

Single base pair changes in DNA that vary among individuals.

Relative Fitness (W)

The average number of offspring of a genotype divided by the average number of offspring of the most fit genotype.

Selection Coefficient (s)

Measures strength of selection against a genotype

Mutation frequency (μ)

Probability that an allele is altered by a new mutation.

Hardy-Weinberg Equilibrium

A principle stating that the genetic variation in a population will remain constant from one generation to the next in the absence of disturbing factors.