Chromosomes, carriers, confusing! Get simple definitions that'll demystify doctor-speak.
By Emily Kimber
Genes: Pieces of DNA that hold hereditary information, passed from parents to their children.
Genetics: The scientific study of heredity -- or the study of how particular traits are transmitted from parents to their children.
Genetic code: The language that explains a person's DNA make-up.
Genetic screening: Tests that identify whether you are at risk for a certain genetic disease or at risk for passing the disease to your children.
Genotype: Your entire genetic makeup, including traits that aren't outwardly observable.
Imprinting: The "memory" held by a chromosome as to which parent it was inherited from. A gene can be expressed differently depending on whether it comes from your father or your mother.
Late-onset disorders: Disorders that can have both environmental and genetic causes (e.g.: cancer or heart disease.) Genetic tests can indicate a predisposition for these diseases -- which means you may develop the disease, not that you definitely will.
Mutation: A change in DNA.
Mutant gene: a gene that has changed so that the normal transmission and expression of a trait is affected.
Newborn screening: a preventive blood test for newborns to detect disease-related abnormalities or deficiencies in gene products.
Phenotype: Traits that are outwardly observable, such as hair colour and height. Phenotypic traits aren't always inherited.
Predictive and presymptomatic testing: Types of testing are used to detect gene mutations associated with disorders that appear later in life.
Prenatal diagnosis: Genetic testing of a fetus that is done when there is believed to be a risk of the child developing genes associated with mental retardation or physical deterioration. (Down Syndrome is one of the most common genetic diseases screened by this method.)
Recessive: A trait or disorder that appears only in a child who has received two copies of the same mutant gene, one from each parent.
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.
For more information on how genetic testing can change your life, pick up the February/March 2006 issue of Homemakers.
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