Ch. 6 Pedigree Analysis, Applications, and Genetic Testing Flashcards
pedigree
pictorial representation of a family history outlining the inheritance of one or more traits or diseases
proband
a person having a trait or disease for whom a pedigree is constructed
consanguinity
mating between related individuals
genetic mosaic
condition in which regions of tissue within a single individual have different chromosome constitutions
dizygotic twins
nonidentical twins that arise when two different eggs are fertilized by two different sperm
monozygotic twins
twins that arise when a single egg fertilized by a single sperm splits into two separate embryos; also called identical twins
concordance
percentage of twin pairs in which both twins have a particular trait
genetic counseling
educational process that attempts to help patients and family members deal with all aspects of a genetic condition
ultrasonography
procedure for visualizing a fetus in which high-frequency sound is beamed into the uterus; sound waves that encounter dense tissue bounce back and are transformed into a picture of the fetus
amniocentesis
procedure used for prenatal genetic testing to obtain a sample of amniotic fluid from a pregnant woman. a long sterile needle is inserted through the abdominal wall into the amniotic sac to obtain the fluid
chorionic villus sampling (CVS)
procedure used for prenatal genetic testing in which a sample piece of the chorion (the outer layer of the placenta) is removed from a pregnant woman. a catheter is inserted through the vagina and cervix into the uterus; suction is then applied to remove the sample
karyotype
the complete set of chromosomes possessed by an organism; usually presented as a picture of a complete set of its metaphase chromosomes
maternal blood screening test
method of screening for genetic conditions in a fetus by examining levels of certain substances in the blood of the mother. for example, the level of a-fetoprotein in maternal blood provides information about the probability that a fetus has a neural-tube defect
noninvasive prenatal genetic diagnosis
genetic test performed on a fetus without taking a tissue sample from the fetus; usually performed by testing fetal DNA found within the maternal blood
fetal cell sorting
separation of fetal cells from maternal blood. genetic testing on the fetal cells can provide information about genetic diseases and disorders in the fetus
preimplantation genetic diagnosis (PGD)
genetic testing on an embryo produced by in vitro fertilization before implantation of the embryo in the uterus
newborn screening
testing of newborn infants for certain genetic disorders
presymptomatic genetic testing
testing to determine whether a person has inherited a disease-causing gene before the symptoms of the disease have appeared
heterozygote screening
testing of members of a population to identify heterozygous carriers of a disease-causing allele who are healthy but have the potential to produce children who have the disease
direct-to-consumer genetic test
test for genetic condition that can be purchased directly by a consumer without the involvement of a physician or other health-care provider
Genetic Information Nondiscrimination Act (GINA)
U.S. law prohibiting health insurers from using genetic information to make decisions about health-insurance coverage and rates; prevents employers from using genetic information in employment decisions; also presents health insurers and employers from asking or requiring a person to take a genetic test
