Inheritance And Disease Flashcards
Where do you inherit mitochondrial DNA come from
All mitochondria/mitochondrial DNA is inherited from the mother
What does imprinting mean
One allele is active while the other is inactive
What is mosaicism
An error in cell division, the same cells have different genetic make up
What does Mendelian inheritance mean
Mendelian inheritance refers to certain patterns of how traits are passed from parents to offspring
What are the different types of Mendelian inheritance
Autosomal recessive
Autosomal dominant
X-linked
How does an autosomal recessive manifest
An autosomal recessive disease manifests in a homozygous state
For offspring to inherit a autosomal recessive how many defective genes do they need to inherit
For an autosomal recessive disease to be inherited 2 defected genes need to be inherited 1 from each parent
What is the chance of getting an autosomal recessive disease
25%
What is the chance of been a carrier of an autosomal recessive disease
50%
What is the chance of an affected child’s sibling been a carrier of an autosomal recessive disease
66.6%
Who is more affected by autosomal recessive disease
Males and females are affected equally
What is an example of an autosomal recessive disease
Cystic fibrosis
What does a autosomal dominant disease manifest in
An autosomal dominant disease manifests in a heterozygous state
Who is affected most by autosomal dominant diseases
Males and females are affected equally
Does autosomal dominant disease affect single or multiple generations
Multiple generations
Why can an offspring get a autosomal dominant disease if the parents are unaffected
Gonadal mosaicism
Mother has reduced penetrance
Mother has variable expression
How many defect genes do you need to inherit a autosomal dominant disease
Only one gene is needed so a 50% chance that offspring can be affected
What is an example of an autosomal dominant disease
Huntingtons disease
What causes an x-linked disease
Caused by a mutation on the X chromosomes
How is an x-linked disease passed to offspring
The transmission of an x-linked is never male to male because the son will get the X chromosome from the mother so transmission will be female to male
Who is more affected by x-linked diseases
Males are more affected
Females will be carriers of the disease but wont suffer
Are x-linked diseases recessive or dominant
X-linked diseases can be both recessive and dominant
What is an example of a recessive x-linked disease
Duchennes muscular dystrophy
What is an example of a dominant x-linked disease
Alports syndrome
What does homozygous mean
A cell is said to be homozygous for a particular gene when identical alleles of the gene are present on both homologous chromosomes
What does heterozygous mean
Diploid organism is heterozygous at a gene locus when its cell contains two different alleles of a gene
What could be the cause of a disease
Genetic cause
Multifactorial cause
Environmental cause
What are examples of genetic diseases
Down syndrome
Cystic fibrosis
Huntingtons disease
Haemophilia
What are examples of multifactorial diseases
Spina bifida
Cleft palate
Diabetes
Schizophrenia
What are examples of environmental factors which could causes disease
Poor diet
Infection
Drugs
Accident
