Module 5 - Part 2

Question 1

Centimorgan (cM)

Answer 1

• is a unit of genetic measurement
• doesn’t calculate actual distance
• RF of 1% = 1 cM
• the larger the cM, the greater the distance between two genes

Question 2

What does recombinant frequency tell us

Answer 2

It tells us:
- whether two genes are linked (RF less 0.5)
- whether two genes are independently assorted (RF = 0.5)

Question 3

Genetic Linkage Analysis

Answer 3

A statistical method used in genetics to identify the chromosomal regions/genes that co-segregate with disease phenotypes

Question 4

Haplotype (haploid + genotype)

Answer 4

The alleles present on a single chromosome from one parent; are inherited together

Question 5

Genotype

Answer 5

The genetic makeup of an organism considering both pairs of chromosomes

Question 6

DNA Polymorphism

Answer 6

alternative forms of a genomic locus that differ in nucleotide seq or length

Question 7

SNP

Answer 7

single nucleotide polymorphism

Question 8

SSR

Answer 8

single sequence repeat (20-30 repeats)

Question 9

VNTR

Answer 9

variable number of tandem repeats (several hundred repeats)

Question 10

RFLP

Answer 10

restriction fragment length polymorphism (review slide)

Question 11

Polymorphisms are ___________ that can be used to narrow down the location of disease alleles

Answer 11

DNA Markers - a DNA seq. of known location on a chromosome
- to identify disease alleles can use: genetic mapping or seq the linked locus
- pedigree must be large enough to see recombinants

Question 12

Limitations of Linkage Analysis (4)

Answer 12

• size of pedigree analyzed
• presence of multiple mutant alleles
• mutations in different genes that cause the same disease
• not possible for multifactorial or complex traits

Question 13

Genome Wide Association Studies (GWAS)

Answer 13

• looks for genetic associations between SNPs & traits by looking at SNPs across the whole genome in a large pop.
• ex. Manhatten plot
• dots above threshold = linked to trait (significant p value)
• dot = SNP, x-axis = genomic location, y-axis = association level (linkage)

Question 14

GWAS - how is it done

Answer 14

1. obtain SNP profiles for each member of the test pop. (1,000-10,000) expressing the phenotype
2. if case-control, control to control pop. (?)
3. identify SNPs associated with differences in individuals that have the trait/disease
4. determine whether there are any association between SNPs on the same haplotype (“narrow down” responsive genes)
5. identify regions of the genome that influence trait expression

Question 15

What type of disease is breast cancer?
What are the 4 main types?

Answer 15

• It is a heterogenous disease
• 4 main types classified based on the protein markers found on outside of the cell
  1. H&E
  2. ER
  3. PR
  4. HER2
  (triple - is the most severe as there is no targeted treatment: ER-/PR-/HER2-)

Question 16

Chemotherapy

Answer 16

Targets fast dividing cells (ie. cancer cells but also hair/GI cells)

Question 17

Prognostic value

Answer 17

Patient with hormone receptor-positive tumours have better survival rates than those who have HR-negative tumours

Question 18

Personalized medicine

Answer 18

A treatment plan is created based on the profile of molecular markers in the pt’s tumour
- fewer side effects & less damage to surrounding tissue
- targeted therapeutics (binds to estrogen receptors)

Question 19

Dr.Juliet Daniel Lab Research Q

Answer 19

Do black women have a SNP (or SNPs) that increases their risk for aggressive and highly fatal treat cancer subtypes?