Genes - Lecture 19

Question 1

What are the benefits of identifying a disease gene?

Answer 1

Genetic testing
Development of new therapies

Question 2

What are the three types of identifying a disease gene?

Answer 2

Pedigree analysis
Linkage analysis
Positional cloning of the disease gene

Question 3

What is the purpose of pedigree analysis?

Answer 3

Investigate the occurrence of the disease in families to determine what type of disease mutation
It displays a family tree to map family members affected

Question 4

What is the purpose of linkage analysis?

Answer 4

Look for evidence of genetic linkage between the disease gene and genetic markers
Can map the disease gene as precisely as possible
Identify recombinant events between genetic markers

Question 5

What is positional cloning of the disease gene?

Answer 5

Select candidate genes in the region of the chromosome
Look for disease associated mutations in each candidate gene
Locate disease associated gene on the chromosome

Question 6

What are the two requirements for DNA markers?

Answer 6

Must be polymorphic
Must be easy to assay

Question 7

What are some common DNA markers?

Answer 7

Short term tandem repeats
Single nucleotide polymorphisms

Question 8

What are STRs?

Answer 8

Tandem repeats of a short sequence, usually 2-4 nucleotides in non coding sequences

Forensic testing
DNA profiles from crime scenes

Question 9

What are SNPs?

Answer 9

Most in non coding DNA
A genomic variant at a single base position in the DNA

Linkage analysis
SNP genotyping

Question 10

What is a genechip?

Answer 10

Used to do SNP genotyping
Each SNP is tested for linkage with the disease phenotype using the appropriate genetic model
This identifies several SNPs in a region of the genome where the disease gene must be located

Question 11

What is the process of positional cloning of the disease gene?

Answer 11

The location in the genome is known for SNPs showing linkage with the disease
We can identify candidate genes by inspecting the human genome sequence in that region

Question 12

What is the process of whole genome sequencing?

Answer 12

Sequence whole genomes from affected and unaffected members of the pedigree
Identify rare variants shared only by the affected individuals
Identify potentially causative variants in candidate genes
Investigate functional consequences of the potentially causative variants