Term
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Definition
| a stage in early animal development (typically the sixteen cell stage in mice) characterized by the formation of a multicellular spherical shell enclosing a fluid-filled cavity (the blastocoel). |
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Term
| Chimera (chimeric organism) |
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Definition
| an organism or recombinant DNA molecules created by joining DNA fragments from two or more different organisms. Also refers to the ¡°founder¡± mouse when creating knockout mice; founders carry cells from two organisms ? a) the ¡°normal¡± blastocyst and b) the transfected ES cells which were injected into the blastocyst |
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Term
| Concatamer (integration of recombinant DNA) |
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Definition
| occurs when the entire genome of the vector including the bacterial plasmid is integrated into the host genome. It is the DNA transgene fragments that attach to each other in unpredictable quantities within the pronucleus arranging into linear structures of unknown copy number. |
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Term
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Definition
| number of DNA segment that integrated into the genome. |
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Term
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Definition
| the technique of freezing tissues or cells or other biological materials at very low temperatures in which the materials remain genetically stable and metabolically inert. Cryopreservation may involve freezers (-80C), or preservation with dry ice (-79C) or liquid nitrogen. |
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Term
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Definition
| the exposure of cells to rapid pulses of high-voltage current which renders the plasma membrane of the cells permeable thus allowing transfection. |
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Term
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Definition
| resulting from conditions within the organism rather than externally caused; derived internally |
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Term
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Definition
| a cell of the early embryo that can replicate indefinitely and which can differentiate into any other typed cells in the organism. Stem cells serve as a continuous source of ne cells. |
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Term
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Definition
| factors, such as extrachromosomal DNA and environmental stressors, which influence the expression of a chromosomally integrated gene. |
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Term
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Definition
| effects of one gene modified by one or several other genes, which are sometimes called modifier genes. The gene whose phenotype is expressed is said to be epistatic, while the phenotype altered or suppressed is said to be hypostatic. Epistasis can be contrasted with dominance, which is an interaction between alleles at the same gene locus. |
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Term
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Definition
| externally caused rather than resulting from conditions within the organism; derived externally. |
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Term
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Definition
| a DNA molecule that replicates on its own in a host cell and can be used as a vehicle in the laboratory for replicating other types of DNA. |
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Term
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Definition
| crossing of a hybrid with one of its parents or an individual genetically similar to its parent, in order to achieve offspring with a genetic identity which is closer to that of the parent |
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Term
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Definition
| all the genetic material in the chromosomes of a particular organism; its size is generally given as its total number of base pairs. |
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Term
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Definition
| genetic constitution of an individual cell or organism. When referring to microinjected transgenics, mice can be homozygous (transgene is present on both chromosomes in a pair), hemizygous (transgene is present on only one chromosome in a pair), or wild type (transgene is not present on either chromosome in a pair). When referring to KO mice the corret terms are homozygous (sometimes called null mice), heterozygous and wild type respectively. |
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Term
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Definition
| transgene DNA is introduced into the pronucleus and one of the embryonic cells has gave rise to reproductive organs, resulting in production of gametes with the transgene. |
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Term
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Definition
| containing two different alleles of the same gene. |
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Term
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Definition
| the exchange of DNA fragments between two DNA molecules or chromatics of paired chromosomes (during crossing over) at the site of identical nucleotide sequences. |
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Term
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Definition
| refers to DNA of allelic chromosomal segments. More recently, used in a looser sense to mean any type of relatedness indicative of a common evolutionary origin, whether within or between species. |
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Term
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Definition
| containing two copies of the same allele |
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Term
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Definition
| having or characterized by one or more genes (as in a genetic deficiency or in an X chromosome paired with a Y chromosome) that have no allelic counterparts |
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Term
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Definition
| the presence of two populations of cells with different genotypes in one individual who has developed from a single fertilized egg. Mosaicism may result from a mutation during development which is propagated to only a subset of the adult cells. |
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Term
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Definition
| a heritable change in DNA sequence resulting from mutagens. Various types of mutations include frame-shift mutations, misssense mutations, and nonsense mutations. |
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Term
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Definition
| DNA sequences or chromosomal segments that have close similarity between species. Ex, the major human sex-determining gene is SRY and its ortholog in mouse is the Sry gene. |
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Term
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Definition
| nonallelic DNA sequences or chromosomal segments that have similarities within a species, indicative of a close relationship which may or may not have predated speciation. Ex. The two different human ¥á-globin genes are paralogous. |
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Term
| Penetrance and expressivity |
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Definition
| penetrance is the proportion of individuals carrying a particular variation of a gene (allele or genotype) that also express an associated trait (phenotype). Expressivity is variations in a phenotype among individuals carrying a particular genotype. This differs from penetrance, which refers to the likelihood of the gene generating its associated phenotype at all, as determined by the proportion of individuals with a given genotype who also possess the associated phenotype. In contrast, expressivity refers to the influence of an expressed gene at the level of particular individuals. |
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Term
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Definition
| the observable characteristics of a cell or organism. Often caused by a specific gene(s). |
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Term
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Definition
| a combination of DNA molecules of different origin that are joined using recombinant DNA technologies. |
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Term
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Definition
| pertains to the body wall of an animal; of the body |
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Term
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Definition
| two genetic loci on the same chromosome. Syntenic loci are not necessarily linked: if they are sufficiently far apart on the chromosome they will not cosegregate more than by random chance. |
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Term
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Definition
| a group of linked genes in one species is paralleled by a linkage group between orthologous genes in another species. |
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Term
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Definition
| having the potential for developing in various specialized ways in response to external-internal stimuli; of a cell or part. Totipotent cell has the capacity to form an entire organism. The only totipotent cells are the fertilized egg and the first 4 or so cells produced by its cleavage |
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Term
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Definition
| pluripotency refers to a stem cell that has the potential to differentiate into any of the three germ layers: endoderm (interior stomach lining, gastrointestinal tract, the lungs), mesoderm (muscle, bone, blood, urogenital), or ectoderm (epidermal tissues and nervous system). |
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Term
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Definition
| a technique to create transgenic mouse. The prepared DNA transgene, usually cloned in a plasmid DNA vector, is injected into the nucleus of a mouse embryo during the pronuclear period immediately following fertilization. Only small amount of transgene DNA is injected (approximately 2 or 3 picoliters). |
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Term
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Definition
| this term describes an organism that has had genes from another organism put into its genome through recombinant DNA techniques. These animals are usually made by microinjection of DNA into the pronucleus of fertilized eggs, with the DNA integrating at random. |
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Term
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Definition
| an organism whose genetic material has been altered using genetic engineering techniques. These techniques, generally known as recombinant DNA technology, use DNA molecules from different sources, which are combined into one molecule to create a new set of genes. This DNA is then transferred into an organism, giving it modified or novel genes. |
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