Flashcards in Genetics Deck (40):
Which direction is DNA replicated in?
A 5 to 3 direction
How many bonds are present between Adenine and thymine?
How many bonds are present between guanine and cytosine?
Which base is replaced in RNA and what with?
Thymine is replaced by uracil
When does cell division occur?
When does DNA replication occur?
During the S phase
What is an exon?
Coding part of a gene
What is an intron?
Non-coding part of a gene
What is a polymorphism?
A variation in the human genome that does not cause a disease in its own right
What is a mutation?
A gene change that causes a genetic disorder
What is an Achrocentric chromosome?
A chromosome where the short arm is either non-existent or so small its insignificant
Whole extra or missing chromosome
Rearrangment of chromosomes
What is a Robertsonian translocation?
Two achrocentric chromosomes stuck end to end
What is a reciprocal translocation?
When the bottom of two adjacent chromosomes are attached to each other
Define somatic mosaicism
One genetic change that contributes to a disease
Which test is used for big genetic changes?
aCGH - deletions and duplications
Which test is used for small genetic changes?
PCR then sanger sequencing - one base change
A genetic variation that causes a disease
A genetic variation that is prevalent in the population and is not itself disease causing
Is PCR used when a specific part of the the genome needs to be looked at or is the section unknown?
Change in one base
Adds one base
Deletion out of frame
Deletes one base
Deletion in frame
Deletes three bases
What is the only thing aCGH detects?
The likelihood of having the disease if you have the gene mutation
Do mendelian disorders have a high or low penetrance?
What is the mechanism of x-inactivation?
Single nucleotide polymorphism (SNP)
Alterations in the DNA sequence which occurs in every 100 to 300 base pairs
Copy Number variants (CNV)
Extra or missing stretches of DNA - deletions or duplications
Sequence variations within a gene
Change in amino acids
Unchanged amino acids
Sequence variations in DNA between genes
Single nucleotide polymorphism
Copy Number Variants
4 Types of non-mendelian inheritance
Where does methylation occur?
On the cystine base before guanine
What does methylation prevent?
Difference in gene expression depending on whether the gene is maternally or paternally inherited
What is the most common base mutation?
C to T
Which parent is most mitochondrial disease inherited from?