Multifactorial Inheritance/ Finding Disease

Question 1

________ is an example of allelic heterogeneity, where many alleles appear to have similar clinical presentations and can contribute to varying levels of disease.

Answer 1

Cystic fibrosis

Question 2

__________ is an example of locus heterogeneity, where variants in different genes all results in identical clinical presentation of this disease.

Answer 2

Early onset Alzheimer’s Disease

Question 3

_________ and _________ is an example of phenocopy in which an environmentally caused phenotype mimics the genetic versions of that trait.

Answer 3

Type II diabetes and Thalidomide-induce limb malformation versus genetically induced limb malformation

Question 4

A higher _________ for disease in MZ than DZ twins suggests that genetic variation contributes more than variation in non-genetic factors.

Answer 4

Concordance

Question 5

The ________ of a trait is the proportion of total variance in a trait that is due to variation in genes.

Answer 5

Heritability

Question 6

How is a genetic association study performed?

Answer 6

Tagged by polymorphic DNA markers and allele frequencies are compared in the cases versus the controls.

Question 7

What are the two fatal flaws in gene-by-gene case control design?

Answer 7

1. True multiple testing correction must include all tests, even those done that may not have been published. 2. It is not possible to ethnically match cases and controls

Question 8

________ studies the gene directly through DNA sequencing and is most useful when _________

Answer 8

Candidate gene sequencing; candidates are positive from GWAS

Question 9

Candidate gene association studies is the most commen type of genetic study and is a powerful tool for ____________

Answer 9

Common risk alleles with small to moderate effects

Question 10

______ and _______ are hypothesis driven studies, whereas, ________ and _________ are hypothesis-free approaches.

Answer 10

Candidate gene sequencing, candidate association studies, genetic linkage studies, genome-wide association studies.

Question 11

In __________, the researcher searches in the genome for segments disproportionately co-inherited along with disease through multiplex families.

Answer 11

Genome Linkage Studies

Question 12

___________ searches for SNP’s with significantly different allele frequencies in cases versus controls.

Answer 12

Genome-Wide Association Studies

Question 13

_____________ combines hypothesis based and hypothesis-free approaches and distinguishes from potentially causal variants from non-pathological variation.

Answer 13

Exome sequencing

Question 14

What are the three commonly used polymorphic DNA markers?

Answer 14

1. Microsatellite 2. Single-nucleotide polymorphisms (SNP’s) and 3. Copy Number Variations (CNV’s)

Question 15

CNV’s are individually __________ yet collectively _________

Answer 15

rare; common

Question 16

__________ uses known biology to determine what the gene is based on function

Answer 16

Functional cloning

Question 17

________ uses known mapping to determine position and function of different genes

Answer 17

Positional cloning

Question 18

________ are used in forensic and linkage studies

Answer 18

Microsatellites

Question 19

___________ are basically common genomic deletions and there is uncertainty in how often they are causal for human disease (mostly, they are not)

Answer 19

Copy Number Variations (CNV’s)