Genetically Modified Organisms, DNA Barcoding, and Genetic Markers

Vocabulary flashcards covering Genetically Modified Organisms, DNA barcoding methodologies, and molecular genetic markers in biology and aquaculture.

Genetically Modified Organism (GMO)

An organism whose genome has been artificially altered by directly integrating or modifying single or multiple genes to alter a targeted trait.

Transgenic Organism

A genetically modified organism that contains a DNA sequence or gene artificially introduced from a completely different species.

Transgenesis

The introduction of an exogenous gene or transgene into a living organism so that it acquires a new property that can be passed on to its offspring.

Fluorescent Transgenic Zebrafish

A transgenic model developed in 1999 by Dr. Z. Gong by microinjecting jellyfish green fluorescent protein genes into zebrafish eggs, paving the way for commercial GloFish.

Growth Hormone (GH) Gene

The most widely used target gene in aquatic GMO modification, utilized to accelerate growth rates and enhance food conversion efficiency.

Anti-freeze Protein (AFP) Gene

A target gene integrated into cold-water aquatic species like Atlantic salmon to enhance low-temperature and cold tolerance.

Gene Knockout (KO)

The permanent disruption or deletion of a target gene at the genomic DNA level, resulting in zero functional protein product.

Gene Knockdown (KD)

The temporary reduction or suppression of gene expression at the RNA level without modifying genomic DNA, leading to a non-heritable reduction in protein levels.

Genetic Engineering

A broad category of laboratory technologies used to alter an organism's DNA, often introducing foreign genes from different species.

Gene Editing

A precise subset of genetic technologies focused on making localized changes, deletions, or substitutions within an organism's own genome without inserting foreign DNA.

DNA Barcode

A short, standardized DNA sequence from a uniform location on the genome used for taxonomic identification of biological species.

Paul D. N. Hebert

The scientist known as the 'Father of DNA Barcoding' who developed sequence-based specimen identification in 2003.

Cytochrome c Oxidase Subunit I (COI)

A $648\text{--}\text{bp}$ fragment near the 5'-end of the mitochondrial gene serving as the standard DNA barcode marker for animal species.

rbcL

The large-chain subunit gene of ribulose-1,5-bisphosphate carboxylase/oxygenase, used as a first-pass plant chloroplast DNA barcode marker for genus-level resolution.

matK

The maturase K gene in plant plastid genomes, used as a second-pass DNA barcode marker to provide higher species-level resolution among closely related plant taxa.

Internal Transcribed Spacer (ITS)

A non-coding region of the nuclear ribosomal cistron adopted as the primary standard DNA barcode region for fungal species.

BOLD Systems

The Barcode of Life Data System, a workbench and reference library database for uploading, managing, and identifying species using DNA barcodes.

FASTA File (.fas)

The standard text-based sequence file format identified by a '>' symbol preceding the sequence name on the first line, followed by nucleotide bases on the second line.

DNA Metabarcoding

An automated approach coupling high-throughput sequencing with DNA barcoding to simultaneously identify multiple species from mass collections or environmental samples.

Environmental DNA (eDNA)

Genomic DNA extracted directly from environmental media such as water, soil, air, or snow without capturing or isolating the target organisms.

MinION

A pocket-sized, portable long-read DNA sequencer developed by Oxford Nanopore Technologies that enables real-time, on-site genetic analysis.

Genetic Marker

Any observable characteristic or polymorphic DNA sequence whose inheritance can be tracked to identify genetic differences between individuals or populations.

Polymorphism

The occurrence of multiple distinct structural or sequence variations at a specific gene or genomic locus within a population.

Southern Blotting

A non-PCR molecular hybridization method developed by Edward Southern in 1975 that uses labeled probes to identify restriction-digested DNA fragments on a membrane.

Polymerase Chain Reaction (PCR)

An in vitro technique invented by Kary Mullis in 1983 that exponentially replicates specific target DNA regions using primers, dNTPs, and heat-stable DNA polymerase.

Sanger Sequencing

The dideoxy chain-termination technique developed by Frederick Sanger that uses modified chain-terminating nucleotides to determine precise DNA base sequences.

Random Amplified Polymorphic DNA (RAPD)

A PCR-based technique utilizing short, arbitrarily chosen single primers to amplify unknown genomic regions without prior sequence knowledge.

Restriction Fragment Length Polymorphism (RFLP)

A molecular marker technique where DNA is digested with restriction endonucleases, yielding variable fragment lengths due to sequence mutations at recognition sites.

Amplified Fragment Length Polymorphism (AFLP)

A multi-locus molecular fingerprinting method that combines restriction enzyme digestion, adapter ligation, and selective PCR amplification.

Microsatellites (SSR)

Simple Sequence Repeats consisting of tandemly arranged short repeat units of $1\text{--}6\text{ bp}$ evenly distributed throughout coding and non-coding genomic regions.

Single Nucleotide Polymorphism (SNP)

A single base pair variation at a specific nucleotide location in a DNA sequence caused by a point mutation.

Quantitative Trait Loci (QTL)

Specific genomic regions containing genes linked to quantitative phenotypic traits such as growth rate, disease resistance, or environmental tolerance.

DNA Microarray

An array platform with thousands of microscopic DNA probes attached to a solid surface used to monitor expression levels of many genes simultaneously.

Expressed Sequence Tag (EST)

A short single-pass cDNA sequence read of $300\text{--}1000\text{ bp}$ representing genes actively expressed in a particular tissue or cell population.

Transcriptomics

The study of the complete set of RNA transcripts (mRNA, non-coding RNA) produced by a genome under specified developmental or environmental conditions.