Lec 8. Pedigree Analysis and Genetic Testing Flashcards
Define discontinuous characteristics
relatively few phenotypes
Define Continuous characteristics
Continues distribution of phenotypes
When do continuous characteristics occur?
when genes at many loci interact
Define polygenic characteristics
characteristics encoded by genes at many loci
What is an example of continuous characteristics?
skin pigmentation
What is FH (familial hypercholesterolaemia)?
Mutation in several genes causing a faulty LDL receptor thus pts have problems with high cholesterol.
What do physicians prescribe for someone with a high cholesterol?
Statins
What happens if a physician gives a pt with FH statins?
Their cholesterol wont go down with any statins.
What is a good polygenic characteristic example?
FH and Type 2 Diabetes.
Human disease is a combination of what two things?
Genetics and environment
What is heterosis/hybrid vigor?
Is the improved/increased function of any biological quality in a hybrid offspring of pure bred strains.
What are some characteristics of heterosis/hybrid vigor?
bigger size,growth, fertility
What is a perfect example of heterosis/hybrid vigor?
Mules
What is adermatoglyphia?
pts dont have fingerprints on hands or feet.
What is a good example of autosomal domaint?
Adermatoglyphia
Pertaining to pedigrees how do you know if someone was affected with the said trait?
Its colored in completely
Pertaining to pedigrees how do you know someone is a carrier with said trait?
Will have a dot
Pertaining to pedigrees how do you know someone is an asymptomatic carrier with said trait?
Has a line splitting it right down the middle
What is a pedigree chart?
A document used by genealogists in the study of inheritance of one or more characteristics pertaining to human family history.
What is proband?
The person from whom the pedigree is initiated.
What is Waardenburg syndrome and what is it a good example of?
Rare genetic disorder characterized by deafness, pigmentation anomalies (white hair) and its an example of autosomal dominant traits.
What are some characteristics in autosomal recessive traits pertaining to the pedigree chart?
Normally appear with equal frequency in both sexes, seem to skip generations and are more likely to appear if incest happens.
What are some autosomal recessive diseases?
CF, sickle cell anemia, and Tay-sachs disease.
What are some characteristics in Autosomal dominant traits pertaining to the pedigree chart?
Appear in equal frequency in both sexes, dont skip generations, unaffected ppl do not transmit the trait, affected ppl have at least one affected parent.
What are some characteristics in X-linked recessive traits pertaining to the pedigree chart?
Appear more often in M than F, not passed from father to son, father can pass allele to daughter who is unaffected but carrier.
What is are two examples of a X-linked reccessive trait?
DMD (Duchenne Muscular dystrophy) and Classic hemophilia.
Which disease is an X-linked dominant form of rickets?
X-linked hypophosphatemia (XLH)
What can XLH cause?
Bone deformity, shortness, bow leggedness.
How does XLH happen?
Mutation in the PHEX gene that inactivated the PHEX protein
What are three characteristics for Y-linked traits?
Only males affected, passed from Fathers to ALL sons, does not skip generations
What are three characteristics for X-Linked recessive traits?
Usually more in M than F. Affected sons usually born to unaffected Mothers (traits skip generations). Half of a Female carrier’s sons are affected
What are three characteristics for X-linked dominant traits?
Usually more F affected than M. Does not skip generations. Affected Fathers pass on trait to all daughters.
Define dizygotic twins
nonidentical twins
Define monozygotic twins
identical twins
Define concordant trait
trait shared by both members of a twin pair
What is concordance?
% of twin pairs that are the same for a trait
True or False? Monozygotic twins do not have the exact same genetic sequence
False. Have the exactly same genetic sequence
Asthma is the result of what?
Hypersensitivity to environmental allergens
What are three special features of human biology that hinder genetic research?
Controlled mating is not possible, long generation time, small family size
What is the Nuremberg code?
Voluntary consent of the human subject is essential.
What is the declaration of Helsinki?
Research with humans should be based on results from lab and animal experiments. Research protocols should be reviewed by an independent committee before starting. Informed consent from participants. Research conducted by medically qualified ppl. Risks shouldnt exceed benefits
What is the Belmont report??
A statement of basic ethical principles and guidelines that should assist in resolving the ethical probs that surround research with humans.
What is the common rule?
Assure compliance by research institutions, requirements for researchers obtaining and documenting informed consent. IRB memberships, function review of research. Additional protection for certain vulnerable research subjects (kids, prisoners etc).
What are two ways to obtain fetal cells for genetic testing?
CVS (catheter through V and sucking some layers of placenta out). Amniocentesis (needle through the moms belly)
Interpreting genetic testing is complicated by what two factors?
Some diseases are causes by numerous mutations, and incomplete penetrance and environmental factors.
What is GINA?
it is illegal to discrimiate against employees or applicants because of genetic info
What is Chloe’s law?
Law that requires all hospitals to administer a pulse oximetry screen on every newborn.
