Genomes and Genomics: Structure, Analysis, and Applications

Vocabulary practice flashcards covering fundamental and advanced concepts in genomics, bioinformatics databases, gene structure and finding, assembly metrics, and emerging technologies.

Pax6

A developmental regulatory gene functioning as a "master switch" for eye formation, where mutations cause severe defects in the eyes, brain, and pancreas, and overexpression suppresses normal cell proliferation.

Operon

A cluster of prokaryotic genes with related functions that are transcribed together under the control of a single promoter and regulatory elements (such as in the lac operon).

Plasmids

Small, typically circular, double-stranded DNA molecules that exist separately from chromosomal DNA, replicate independently, and often carry genes conferring adaptive traits such as antibiotic or heavy metal resistance.

Histones

Major chromatin structural proteins containing basic amino acids (arginine and lysine) that bind to negatively charged DNA to form nucleosomes.

Euchromatin vs. Heterochromatin

Euchromatin consists of loosely coiled, open nucleosomal arrays accessible for transcription, whereas heterochromatin represents densely compacted chromatin where gene expression is repressed.

Pangenome

The totality of genetic material within a collection of genomes from a species or group, divided into the core genome (genes shared by every member) and the accessory genome (genes present in only some members).

Uniparental Inheritance

A non-Mendelian genetic inheritance pattern where offspring inherit organelle genomes (such as mitochondrial or chloroplast DNA) exclusively from a single parent.

Genome Annotation

The process of turning raw genomic sequence data into a meaningful biological understanding of what functional elements, genes, and non-coding parts are doing.

Pseudogenes

Non-functional "dead genes" that have accumulated mutations without deleterious consequences, occurring in unprocessed forms (which may retain promoters and be transcribed) or processed forms.

Alternative Splicing

A post-transcriptional mechanism that allows a single pre-mRNA gene transcript to generate multiple distinct protein isoforms through the differential inclusion or exclusion of exons.

Untranslated Regions (UTRs)

Segments at the $5'$ and $3'$ ends of mature mRNA molecules that are transcribed from DNA but not translated into amino acid sequences.

Shine-Dalgarno Sequence

A conserved prokaryotic ribosome binding site (such as AGGAGG in E. coli) located approximately $8\,\text{bp}$ upstream of start codons that recruits the ribosome for translation initiation.

Codon Usage Analysis

A gene-prediction method that measures the statistical preference of an organism for specific synonymous codons to identify putative protein-coding regions showing similar bias.

Composite Sequence Database

A non-identical compiled sequence archive (such as NRDB or SP+TrEMBL) assembled from multiple primary databases to streamline and consolidate sequence similarity searches.

Secondary Pattern Database

A curated bioinformatics resource (such as PROSITE, PRINTS, or Pfam) derived from primary databases that stores alignments, motifs, fingerprints, or Hidden Markov Models (HMMs) for functional protein family assignment.

Application Programming Interface (API)

A software interface and protocol that establishes a standardized connection allowing separate computers or computer programs to communicate and share data.

De Novo Whole-Genome Shotgun Assembly

A computational method of assembling an entire genome from scratch by randomly fragmenting genomic DNA, sequencing large numbers of overlapping reads, and aligning them without a reference template.

Sequencing Coverage

The average number of independently sequenced reads that align to and represent a specific nucleotide position across the genome.

N50 Metric

An assembly quality metric calculated as the length of the shortest contig or scaffold such that sum of contigs of equal or greater length accounts for at least $50\%$ of the total assembly length.

Non-Synonymous Mutation

A point mutation within a coding region that alters the codon to specify a different amino acid, which has a higher probability of exerting a phenotypic effect than a synonymous mutation.

Hardy-Weinberg Equilibrium

The principle stating that allele ($p + q = 1$) and genotype ($p^2 + 2pq + q^2 = 1$) frequencies remain constant across generations in the absence of evolutionary forces: no mutations, no gene flow, random mating, large population size, and no natural selection.

Enrichment Analysis

A computational analysis that identifies biological functions or pathways statistically over-represented in a defined gene list relative to a curated background ontology database (such as GO or KEGG).

Phylogenomic Incongruence Mechanisms

Evolutionary processes causing conflicting genealogies among gene trees and species trees: incomplete lineage sorting, hybridization/gene flow, and gene duplication and loss.

Pharmacogenomics

A precision medicine field studying how an individual's genomic and transcriptomic variants influence drug activity, metabolic speed, therapeutic efficacy, and adverse reaction risks.

Nanopore Sequencing

A third-generation sequencing method that decodes DNA in real time by passing native strands through a protein nanopore and measuring electrical current fluctuations, generating long reads of up to $\sim 1\,\text{Mbp}$.

Spatial Transcriptomics

A technique that profiles gene expression while preserving exact two-dimensional coordinates in tissue sections, mapping cell-cell communication and microenvironment interactions.

AlphaFold

An artificial intelligence system that predicts the precise three-dimensional folded structures of proteins directly from their primary amino acid sequences.

Minimal Genome Organism

A synthetically engineered organism stripped of all non-essential DNA, containing only the baseline gene set required to sustain independent cellular life.