Basic terms
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DNA (Deoxyribonucleic acid)
Biopolymer molecules, consisting of two polynucleotide chains that are twisted around each other, forming a double helix that carries the genetic instructions for the development, functioning, growth and reproduction of all known organisms. Information in DNA is stored as a code consisting of four chemical bases: adenine (A), guanine (G), thymine (T) and cytosine (C). In eukaryotic cells, DNA is contained in long structures called chromosomes. Prior to cell division, chromosomes are duplicated by DNA replication, providing a complete set of chromosomes for each daughter cell.
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RNA (Ribonucleic acid)
Biopolymer molecules that perform various important functions in coding, decoding, regulation and expression of genes. Information in RNA is stored in the form of a code consisting of four chemical bases: adenine (A), guanine (G), uracil (U) and cytosine (C).
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Line/Strain
A group of animals that carry the same set of genetic traits (mutations and/or transgenes).
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Wild type
The phenotype, genotype, or allele (variant) of a gene that is predominant in a natural population of organisms or in lines/strains of organisms, as opposed to natural or laboratory mutant forms.
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P-elements
Mobile genetic elements found in Drosophila; often used as mutagenic agents in genetic experiments. They may contain various transgenes within themselves.
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PCR
Polymerase chain reaction; a method widely used to quickly obtain millions to billions of copies (full or partial) of a particular DNA sample, allowing, using only a very small amount of DNA, to amplify it (or part of it) to a large enough amount for subsequent detailed study.
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Chromosomes
Filamentous structures of protein and individual DNA molecules that carry hereditary information.
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Driver
A transgene that determines the temporal and/or spatial pattern of expression (activity) of another transgene.
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Transcription activator
A protein that increases the rate of transcription of genetic information from DNA to messenger RNA by binding to a specific DNA sequence.
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Genetic Engineering
The intentional modification of an organism's characteristics by manipulating its genetic material.
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Gene
The basic unit of heredity and the sequence of nucleotides in DNA that codes for the synthesis of a gene product, either RNA or protein.
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Genetic background
The set of features (mutations) of all other genes that can potentially affect the phenotypic expression of the gene (or genes) under study.
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Genetic crossbreeding
The deliberate crossing of two different individuals, as a result of which the offspring bears part of the genetic material of each parent.
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Genotype
The set of allelic variants of the genes of an individual organism.
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Genotyping
The process of determining differences in the genetic make-up (genotype) of an individual by examining its DNA sequence using specific techniques and comparing it to that of another individual or a reference/reference sequence.
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Sequencing
The process of determining the sequence of nucleotides in nucleic acid molecules.
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Mutation
Change in the DNA sequence of an organism. Mutations can result from errors in DNA replication during cell division, exposure to mutagens, or viral infection. Germline mutations (which occur in eggs and sperm) can be passed on to offspring, while somatic mutations (which occur in the rest of the body's cells) are not.
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Point mutation
A genetic mutation in which only one nucleotide is changed, added or removed at a specific location in the genome.
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Transgene
A gene taken from the genome of one organism (or a combination of different genes taken from the genomes of different organisms) and artificially introduced into the genome of another organism.
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Chimeric guide RNA
A two-part version of the naturally occurring guide RNA complex, engineered into a single contiguous sequence. Used to recruit a Cas9 transcriptional activator protein to a specific DNA sequence to control target gene expression.