A GLOSSARY OF GENETICS TERMS

Gene: Basic unit of inheritance for all living organisms. Genome: Genetic endowment of a species. Human Genome Project: Massive international effort to map and sequence all the human genes. Gene mapping: Determining location of genes on chromosomes. Gene sequencing: Determining identity of genes from the distinctive order (sequence) of base pairs, such as A-T and G-C. Chromosome: Threadlike structure in the nuclei of plant and animal cells; it carries the linearly arranged genetic units (genes). DNA: Deoxyribonucleic acid. The basic material of chromosomes is a linear polymer with sub units (nucleotides) made of a sugar (deoxyribose), a phosphate group, and one of four nitrogenous bases. RNA: Ribonucleic acid. Another class of nucleic acid occurring in three forms. messenger, transfer and ribosomal Nucleic acid: Large, chainlike molecule of phosphric acid, sugar and purine and pyrimidine bases. Marker: Gene with a known location on a chromosome. Template: Macromolecular model for another macromolecule, as in the synthesis of RNA from a DNA template Transgenic: Organism, such as a mouse, containing experimentally transferred genetic material from another organism, such as a mammal. Mutation: Abrupt change in the genotype of an organism that is not the result of recombination. Recombination: Formation in offspring of genetic combinations not present in parents. Genotype: The genetic constitution of an individual. Phenotype: The observable characters of an organism; the result of the way the genes are expressed. Genetic defect: Pathological changes that occur by duplication, deletion or rearrangement of DNA Transcription: The process by which RNA is formed from DNA. Nucleotide: The structural unit of nucleic acid.