Amniocyte: A cell from the amniotic fluid that surrounds the fetus during pregnancy.
Biotechnology: The use or development of techniques using organisms (or parts of plants, animals, or humans) to provide or improve goods; services to improve the environment.
Chorionic villi: Finger-like projections growing from the external surface of the chorion that contribute to the formation of the placenta.
Chromosome: A structure that lies inside a cell's nucleus. A chromosome is composed mainly of DNA. Each normal cell of the human body has 23 pairs of chromosomes.
Confidentiality: A fundamental component of the physician-patient relationship, stemming primarily from the Hippocratic oath, in which the physician has the duty to keep confidential all that is confided by the patient.
Cystic Fibrosis: A hereditary disease that effects the mucus secreting glands, sweat glands, etc. The abnormality results in the production of thick mucus, which obstructs the intestinal glands, pancreas, and bronchi. Respiratory infections, which may be severe, are a common complication.
DNA: The molecule that encodes genetic information. DNA is a double-stranded molecule held together by weak bonds between base pairs of nucleotides. There are 4 nucleotides in DNA: adenosine (A), guanosine (G), cytosine (C), and thymidine (T). In nature, base pairs form only between A and T and between G and C, thus the sequence of each single strand can be deduced from its partner.
DNA sequence: The relative order of base pairs, whether in a stretch of DNA, a gene, a chromosome, or an entire genome.
Dominant: A trait or condition that is expressed in individuals who have a single version of a particular gene.
Down's Syndrome: A form of mental subnormality due to a chromosomal defect
Embryo (Early or preimplantation): embryo refers to the first two weeks after the formation of the zygote. Embryo technically refers to the stage from the third to the eighth week of development. Often, the term embryo also encompasses development from the beginning up to the eighth week.
Ethics A system of moral principles or standards that governs conduct.
Fetus: The developing human embryo from the ninth week after fertilization until birth.
Fertilization The event that initiates the development of the oocyte into embryonic development; normally triggered by the entry of a sperm into the ocyte.
Gamete: Mature male or female reproductive cell with a haploid set of chromosomes (in humans there are 23 chromosomes); that is, a sperm or ovum.
Gene: The fundamental physical and functional unit of heredity. A gene is an ordered sequence of nucleotides located in a particular position on a particular chromosome.
Gene expression: The process by which a gene's blueprint is converted into the structures and protein used by the cell to survive and performs its functions within an organism. Expressed genes include those that are transcribed into RNA and then translated into protein and those that are transcribed into RNA but not translated into protein.
Genetic linkage: Nonrandom segregation of genes or markers because they are located to closely
Genetic screening: Analysis of an individual genotype for the presence or absence of a particular DNA sequence, or gene.
Genetics: The study of patterns of inheritance of specific traits and their underlying basis.
Genome: All the genetic material in the chromosomes of a particular organism; its size is generally given as its total number of base pairs.
Genotype: The genetic constitution of an individual.
Germ cells: Egg and sperm cells and the cells that give rise to them
Gestation: The period during which a fertilized egg cell develops into a baby that is ready to be delivered.
Human Genome Project: Research and technology development efforts aimed at mapping and sequencing the genome of human beings.
Huntington's Disease: A jerky involuntary movement particularly affecting the shoulders, hips, and face. The symptoms are due to disease of the basal ganglia. This disease is also accompanied by a progressive dementia. It is inherited as a dominant characteristic, appearing in half the children of the patients with this condition.
Hypothyroidism: Subnormal activity of the thyroid gland. If present at birth and untreated can cause cretinism. In adult life it causes mental and physical slowing, undue sensitivity to cold, slowing of the pulse, weight gain, and coarsening of the skin.
Heterozygous: Having two different alleles at the same position on each of a pair of chromosomes.
Homozygous: Degree of relatedness in appearance, function or structure; having identical alleles at the same position on each of a pair of chromosomes.
Hormone: Chemical substance produced in one part of the body that affect an organ or group of cells in another part of the body.
Human gene therapy: Insertion of normal DNA directly into cells to correct a genetic defect.
In vitro: Literally "in glass;" pertaining to a biological process or reaction taking place in an artificial environment, usually in a laboratory.
In vitro fertilization A technique of medically assisted conception (sometimes referred to as "test tube" fertilization) in which mature ocytes are removed from a woman's ovary and fertilized with sperm in a laboratory.
In vivo Literally "in the living;" pertaining to a biological process or reaction taking place in a living cell or organism.
Infertility Inability to conceive.
IVF In vitro fertilization
Metabolites: A substance that takes part in the process of metabolism. Metabolites are either produced during metabolism or are constituents of food taken in the body.
Mitochondrial DNA: Mitochondria has its own DNA that is unique from other that found in the nucleus of all body cells.
Muscular Dystrophy: Any one of a group of muscle diseases in which there is a recognizable pattern of inheritance.
Mutation: Any change in DNA sequences that results in a new characteristic that can be inherited.
NIH: National Institute of Health, USA
Nucleic acid: A macromolecule composed of sequences of nucleotide bases, DNA or RNA.
Nucleotide: A subunit of DNA or RNA consisting of a nitrogenous bas (adenine, guanine, thymine, or cytosine in DNA; adenine, guanine, uracil, or cytosine in RNA), a phosphate molecule and a sugar molecule (deoxyribose in DNA and ribose in RNA). Thousands of nucleotide and linked to form the DNA or RNA molecule.
Pharmacogenetics: The study of how people respond differently to medicines due to their genetic inheritance.
Plasmid: An extrachromosomal, circular piece of DNA found in the cytoplasm that is capable of replicating and segregating independently of the host chromosome.
Placenta: An organ within the uterus by means of which the embryo is attached to the wall of the uterus. It primary function is to provide the embryo with nourishment
Phenotype: The characteristics of individuals that result from the interaction of their genotypes and their environments.
Polymorphisms: The differences in DNA sequence among individuals. Genetic variations occurring in more than 1 percent of a population would be considered useful polymorphisms for genetic linkage analysis.
Proteins: A large molecule composed of chains of smaller molecules (amino acids) in specific sequence; the sequence is determined by the sequence of nucleotides in the gene coding for the protein. Proteins are required for the structure, function and regulation of the body's cells, tissues and organs, and each protein has a unique function.
RNA: Ribonucleic acid; a chemical found in the nucleus and cytoplasm of cells, it plays an important role in protein synthesis and other chemical activities of the cell. The structure of RNA is similar to that of DNA. There are several classes of RNA molecules, including messenger RNA, transfer RNA, ribosomal RNA and other small RNAs, each of which serves a different purpose.
Recessive: A trait or condition that is expressed only in individuals who have two altered versions of a particular gene, one inherited from their mother, and one from their father.
Sex-linked Diseases: Diseases occurring more often in males, who have the X-chromosome. The disease occurs on the X-chromosome, and there is no 2nd X-chromosome (as in females) to "cancel" out the disease trait. Females must have 2 X-chromosomes with the disease allele.
Somatic cells: Any cells in the body except reproductive cells and their precursors.
Syndrome: The combination of signs and symptoms that occur together in any particular disorder.
Tay Sach's Syndrome: An inherited disorder of lipid metabolism in which abnormal accumulation of lipids in the brain leads to blindness, mental retardation, and death in infancy.
X-linked: Genes carried on the X-chromosome.
Zygote: The fertilized egg; the single cell that is formed when the two haploid sets of chromosomes in the pronuclei of the male and female gametes come together at syngamy. Also used loosely to refer to the early embryo during the first few weeks.
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