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Glossary
- allele
version of a gene at a given locus
- amplicon
copy of a target DNA created by PCR or other amplification methods
- central dogma (of molecular biology)
fundamental tenet of molecular biology stating that DNA is copied via replication, RNA is derived from DNA via transcription, and protein is derived from RNA via translation. The discovery of reverse transcription disrupted the central dogma of molecular biology by showing that genetic information could also flow from RNA to DNA, not just DNA to RNA.
- complementary DNA (cDNA)
DNA produced using an RNA template via the enzyme reverse transcriptase
- compound heterozygote
individual with two abnormal alleles at a given locus, each with a difference polymorphism or mutation.
- deletion
mutation resulting from the removal of base(s)
- DNase
enzyme that degrades DNA
- DNA ligase
enzyme that joins two pieces of DNA
- DNA polymerase
enzyme that uses DNA as a template to produce a complementary strand of DNA; cDNA is made with a type of DNA polymerase called reverse transcriptase (an RNA-dependent, DNA polymerase)
- DNA sequencing
base-by-base determination of the exact sequence of target DNA
- epigenetic
referring to heritable changes to the genome that do not alter the coding sequence
- frame-shift mutation
insertion or deletion of base(s) that alters the reading frame of a coding sequence, thereby changing the amino acids encoded downstream and/or producing a stop codon
- gel electrophoresis
separation of DNA by size via migration in an electric field in an agarose or polyacrylamide matrix
- gene
segment of DNA transcribed into RNA that (i) is translated into a protein or (ii) forms structures such as ribosomes
- genetic variant
alternative forms of a gene which may or may not lead to altered phenotype
- genome
all the genetic material of an organism
- genotype
the alleles at a given locus in an individual; see also phenotype
- haplotype
analogous to genotype, haplotype is the set of alleles (or SNPs) on one chromosome or part of a chromosome that are linked and usually or often inherited together
- heterogeneous
regarding PCR, requiring separate amplification and detection steps
- homogeneous
regarding PCR, having combined amplification and detection steps
- hybridization
process of forming a double-stranded molecule from a single-stranded probe and a single-stranded nucleic acid target
- hybridization probe
type of fluorescently-labeled probe used in real-time PCR that produces signal following hybridization to a target DNA
- missense mutation
base change resulting in coding of a different amino acid
- molecular diagnostics
diagnosis of disease using nucleic acids as analytes, often used synonymously with molecular pathology
- mRNA
messenger RNA, translated into protein
- mutation
generally harmful DNA sequence change; compare to polymorphism
- nucleic acids
deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), the molecules containing the genetic code
- nucleoside
nucleotide lacking a phosphate group
- nucleotide
building block of nucleic acids composed of phosphate group(s), a five-sided sugar molecule, and a nitrogenous base
- oligonucleotide
short sequence of nucleotides, often used as primers for PCR or DNA sequencing
- penetrance
percent expression in a population of the phenotype of a given mutant genotype
- pharmacogenetics
the hereditary basis for inter-individual differences in drug response
- pharmacogenomics
the convergence of pharmacogenetics and genomics used to mean the influence of DNA sequence variation on the effect of a drug on an individual
- phenotype
traits resulting from a given genotype
- point mutation
mutation that changes a single base
- polymerase chain reaction (PCR)
enzymatic in vitro nucleic acid amplification method using temperature cycling to produce repeated cycles of DNA replication
- polymorphism
variant DNA sequence change, typically benign, found in 1% or more of individuals; compare to mutation
- primer
oligonucleotide used in PCR or DNA sequencing to target an area of interest
- primer-dimers
nonspecific products formed during PCR by the interaction of primers
- probe
relatively small piece of DNA or RNA used to find or detect a specific piece of target nucleic acid
- proteomics
study of the entire complement of proteins in organisms
- quantification standard
synthetic nucleic acid standard spiked into samples before processing to serve as a reference in quantitative PCR
- real-time PCR
PCR in which detection of product is simultaneous with amplification
- replication
process of duplicating DNA with DNA polymerase
- restriction endonuclease (RE)
enzyme purified from bacteria that recognizes and cleaves unique sequences
- restriction fragment length polymorphism (RFLP)
polymorphism that changes the electrophoretic banding pattern of DNA fragments generated by digestion with a restriction endonuclease
- single nucleotide polymorphism (SNP)
polymorphism that is a single base change
- Southern blot hybridization
DNA detection method where digested sample is separated by electrophoresis, transferred to a membrane, and probed
- transcription
process of producing mRNA from a DNA template
- translation
process of converting the information contained in mRNA into protein
- uracil-N-glycosylase
enzyme used to prevent amplicon carryover contamination that degrades any DNA containing uracil (uracil-containing DNA is not natural and is produced in vitro during some PCR protocols)
- variant allele
specific alternative forms of a gene, generally causing a known alternative phenotype
- wild-type
normal allele; compare to mutant or variant