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PAS 511 - Genetics

Terms in this set (63)

Acquired Mutations
gene changes that arise within individual cells and accumulate throughout a person's lifetime; also called somatic mutations. (See Hereditary mutation.)
Alleles
variant forms of the same gene. Different alleles produce variations in inherited characteristics such as eye color or blood type.
Amino Acid
any of a class of 20 molecules that combine to form proteins in living things.
Autosome
any of the non-sex-determining chromosomes. Human cells have 22 pairs of autosomes
Base Pairs
the two complementary, nitrogen-rich molecules held together by weak chemical bonds. Two strands of DNA are held together in the shape of a double helix by the bonds between their base pairs. (See Chemical base.)
BRCA 1
a gene that normally helps to restrain cell growth.
BRCA 1 breast cancer susceptibility gene
a mutated version of BRCA1, which predisposes a person toward developing breast cancer.
Carrier
a person who has a recessive mutated gene, together with its normal allele. Carriers do not usually develop disease but can pass the mutated gene on to their children.
Carrier Testing
testing to identify individuals who carry disease-causing recessive genes that could be inherited by their children. Carrier testing is designed for healthy people who have no symptoms of disease, but who are known to be at high risk because of family history.
Chemical Base
an essential building block. DNA contains four complementary bases: adenine, which pairs with thymine, and cytosine, which pairs with guanine. In RNA, thymine is replaced by uracil.
Chromosomes
structures found in the nucleus of a cell, which contain the genes. Chromosomes come in pairs, and a normal human cell contains 46 chromosomes, 22 pairs of autosomes and two sex chromosomes.
Clone
a group of identical genes, cells, or organisms derived from a single ancestor.
Cloning
the process of making genetically identical copies
Contig Maps
types of physical DNA maps that consist of overlapping segments of DNA (contigs) that, taken together, completely represent that section of the genome. (See Physical maps.)
Colonoscopy
examination of the colon through a flexible, lighted instrument called a colonoscope.
Crossing Over
a phenomenon, also known as recombination, that sometimes occurs during the formation of sperm and egg cells (meiosis); a pair of chromosomes (one from the mother and the other from the father) break and trade segments with one another.
Cystic Fibrosis
an inherited disease in which a thick mucus clogs the lungs and blocks the ducts of the pancreas.
DNA Repair Genes
certain genes that are part of a DNA repair pathway; when altered, they permit mutations to pile up throughout the DNA.
Dominant Allele
a gene that is expressed, regardless of whether its counterpart allele on the other chromosome is dominant or recessive. Autosomal dominant disorders are produced by a single mutated dominant allele, even though its corresponding allele is normal. (See Recessive allele.)
Familial adenomatous polyposis:
an inherited condition in which hundreds of potentially cancerous polyps develop in the colon and rectum
Gene
a unit of inheritance; a working subunit of DNA. Each of the body's 20,000 to 25,000 genes contains the code for a specific product, typically, a protein such as an enzyme. (Revised: October 2004)
Gene Deletion
the total loss or absence of a gene.
Gene Expression
the process by which a gene's coded information is translated into the structures present and operating in the cell (either proteins or RNAs).
Gene Markers
landmarks for a target gene, either detectable traits that are inherited along with the gene, or distinctive segments of DNA
Gene Mapping
determining the relative positions of genes on a chromosome and the distance between them
Gene Testing
examining a sample of blood or other body fluid or tissue for biochemical, chromosomal, or genetic markers that indicate the presence or absence of genetic disease.
Gene Therapy
treating disease by replacing, manipulating, or supplementing nonfunctional genes.
Genetic Linkage Maps
DNA maps that assign relative chromosomal locations to genetic landmarks either genes for known traits or distinctive sequences of DNA - on the basis of how frequently they are inherited together. (See Physical maps.)
Genetics
the scientific study of heredity: how particular qualities or traits are transmitted from parents to offspring.
Genome
all the genetic material in the chromosomes of a particular organism.
Genome Maps
charts that indicate the ordered arrangement of the genes or other DNA markers within the chromosomes.
Genotype
the actual genes carried by an individual (as distinct from phenotype that is, the physical characteristics into which genes are translated).
Germ Cells
the reproductive cells of the body, either egg or sperm cells
Hereditary Mutation
a gene change in the body's reproductive cells (egg or sperm) that becomes incorporated in the DNA of every cell in the body; also called germline mutation. (See Acquired mutations.)
Human Genome
the full collection of genes needed to produce a human being.
Human Genome Project
an international research effort (led in the United States by the National Institutes of Health and the Department of Energy) aimed at identifying and ordering every base in the human genome.
Huntington's Disease
an adult-onset disease characterized by progressive mental and physical deterioration; it is caused by an inherited dominant gene mutation.
Imprinting
a biochemical phenomenon that determines, for certain genes, which one of the pair of alleles, the mother's or the father's, will be active in that individual.
Inborn Errors of Metabolism
inherited diseases resulting from alterations in genes that code for enzymes
Leukemia
cancer that begins in developing blood cells in the bone marrow.
Li-Fraumeni syndrome
a family predisposition to multiple cancers, caused by a mutation in the p53 tumor-suppressor gene.
Linkage Analysis
a gene-hunting technique that traces patterns of heredity in large, high-risk families, in an attempt to locate a disease-causing gene mutation by identifying traits that are co-inherited with it.
Melanoma
a cancer that begins in skin cells called melanocytes and spreads to internal organs.
Mutation
a change in the number, arrangement, or molecular sequence of a gene.
Newborn Screening
examining blood samples from a newborn infant to detect disease-related abnormalities or deficiencies in gene products.
Oncogenes
genes that normally play a role in the growth of cells but, when overexpressed or mutated, can foster the growth of cancer.
Penetrance
a term indicating the likelihood that a given gene will actually result in disease
Precancerous Polyps
growths in the colon that often become cancerous.
Predictive Gene Test
tests to identify gene abnormalities that may make a person susceptible to certain diseases or disorders.
Prenatal Diagnosis
examining fetal cells taken from the amniotic fluid, the primitive placenta (chorion), or the umbilical cord for biochemical, chromosomal, or gene alterations.
Recessive Allele
a gene that is expressed only when its counterpart allele on the matching chromosome is also recessive (not dominant). Autosomal recessive disorders develop in persons who receive two copies of the mutant gene, one from each parent who is a carrier. (See Dominant allele.)
Restriction Enzymes
enzymes that can cut strands of DNA at specific base sequences
Retinoblastoma
an eye cancer caused by the loss of a pair of tumor-suppressor genes; the inherited form typically appears in childhood, since one gene is missing from the time of birth.
Screening
looking for evidence of a particular disease such as cancer in persons with no symptoms of disease.
Sex Chromosome
the chromosomes that determine the sex of an organism. Human females have two X chromosomes; males have one X and one Y
Sickle-Cell Anemia
an inherited, potentially lethal disease in which a defect in hemoglobin, the oxygen-carrying pigment in the blood, causes distortion (sickling) and loss of red blood cells, producing damage to organs throughout the body
Somatic Cells
all body cells except the reproductive cells
Tay-Sachs Disease
an inherited disease of infancy characterized by profound mental retardation and early death; it is caused by a recessive gene mutation
Transcription
the process of copying information from DNA into new strands of messenger RNA (mRNA). The mRNA then carries this information to the cytoplasm, where it serves as the blueprint for the manufacture of a specific protein.
Translation
the process of turning instructions from mRNA, base by base, into chains of amino acids that then fold into proteins. This process takes place in the cytoplasm, on structures called ribosomes.
Tumor Suppressor Gene
genes that normally restrain cell growth but, when missing or inactivated by mutation, allow cells to grow uncontrolled. (p53)
X Chromosome
a sex chromosome; normal females carry two X chromosomes
Y Chromosome
a sex chromosome; normal males carry one Y and one X chromosome.
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