Genetic Variation and how it causes Disease (4) Flashcards
(16 cards)
The likelihood of having a disease if you have a gene mutation is called _______
Penetrance
Name the 4 types of Mendelian Inheritance
Autosomal Dominant
Autosomal Recessive
X-Linked
Mitochondrial
In pedigree drawing what is the symbol for a male
A square
In pedigree drawing what is the symbol for a female
A circle
In pedigree drawing what is the symbol for someone affected by a disease
Shaded/black circle/square
In pedigree drawing what is the symbol for a miscarriage
A small triangle
In pedigree drawing what is the symbol for someone who is deceased
circle/square with a diagonal line through it
Autosomal dominant:
If one parent is affected what is the chance that the child will be?
50%
1/2
Autosomal recessive:
If both parents carry the gene what is the chance that the child will be?
1/4
25%
X-linked:
For a female carrier
Half of the male children of a carrier will be ______
Half of the female children will be _____
Affected
Carriers
X-linked:
If an affected male has children
All of the male children will be _____
All of the female children will be ______
Normal
Carriers
A female carrier may show mild features of an X-Linked disease, why?
X-inactivation
In female cells only one X chromosome is active
Therefore half the cells have the working/affected gene
and then some features of the disease will be displayed
Describe Single Nucleotide Polymorphisms (SNP’s)
Alterations to DNA sequence
Roughly 3,000,000 in every person
Polymorphism = A genetic variation that is prevalent in the population and not, in itself, disease causing
For each SNP there are ___ possible genotypes.
Three
eg.
RR Rr rr
Copy Number Variations (CNV’s) are _____ or ______ stretches of DNA
extra
missing
(deletions/duplications)
In “Mendelian” disorders:
High penetrance =
_____ environmental contribution
Small
