Lecture 8 - Human pedigree charts

What do these each represent?

1. Relationship line

2. Line of Descent

3. Sibling ship line

4. Individual line

Monozygotic vs. Dizygotic twins

Why?

Digeorge’s syndrome

• Genotypes

• Cause

C = the correct rearrangement

• the deletion results in a small interstitial deletion

  • Interstitial b/c 2 break points

  • Small b/c breaks are within the same region (11)

What are the phenotypes of Digeorge’s syndrome

• Learning + behavioural problems

• Characteristic facial expressions (facies)

• Heart defects

• + others

How do we confirm/ test for Digeorge’s syndrome?

• what method?

Probe to 22q11 (region we are testing for presence of) + 22q13 (control, should be present regardless)

What are the 5 possible inheritance patterns?

Autosomal Dom + Recessive

X- linked Dom + Recessive

Mitochondrial

What type of Inheritance pattern does Digeorge’s syndrome have?

Autosomal dominant

Define Pleiotropy

When a mutation has more than one phenotype

is Digeorge’s syndrome pleiotropy present or absent

PRESENT

Define penetrance

% of individuals with mutant allele that have the mutant phenotype

Is Digeorge’s syndrome complete (100) or incomplete (<100) penetrance?

Complete

Define Expressivity

Severity of phenotype

is Digeorge’s syndrome Narrow or broad expressivity?

Broad