Lecture 17 Flashcards
What do sexually reproduced diploid organisms inherit?
1/2 of their DNA from each parent
What is DNA packed onto?
Chromosomes
How many sets of each chromosome does a diploid organism have?
2, called a homologous pair
What is an allele?
An alternative form of a genetic variant located the same place in the gene
What could two different alleles mean?
You have two different versions of the same protein
How is genetic variation measured?
Through phenotypes
What is a phenotype?
The observable characteristic or traits of an individual
What does an individual’s phenotype depend on?
Their genotype
What is a genotype?
The combination of alleles a person has for a particular genetic variant
What are the simplest form of inheritance to track?
Dominant and recessive traits
What is a dominant allele?
An organism with at least one dominant allele will show that alleles phenotype
What is a recessive allele?
An organism will only show a recessive allele’s trait when both alleles are the same
What is a gain of function variation?
It causes the protein to work too well or do something new. They often follow a dominant inheritance patterns
What is a loss of function variation?
It causes the protein to no longer work. They often follow a recessive inheritance pattern
What is a monogenic trait?
An inherited trait that is controlled by a single gene. They are generally discrete and follow simple inheritance patterns. Environment may influence
What is a polygenic trait?
An inherited trait that is controlled by multiple genes. These do not follow obvious inheritance patterns but are common in families and categorised in terms of risk. Environment may influence
What is retinitis pigmentosa?
A dominant (GOF) retinal degenerative disease caused by variants in the Rhodopsin receptor protein causing night blindness and complete loss of vision over time from overworking the rod cells leading to apoptosis.
What is phenylketonuria?
A recessive (LOF) inherited inability to metabolise phenylalanine
How can we detect genetic variants?
Through genotyping
What could genotyping help confirm?
The specific cause of disease, confirm the inheritance pattern, predict the future health/disease progression
What are the three different methods to determine genotype?
PCR-RFLP, fluorescence-based methods, genome sequencing
What is PCR?
The polymerase chain reaction which is a lab-based method to make many copies for a specific segment of DNA
What are the reaction components of PCR?
DNA sample, primers, polymerase, nucleotides
What are the three steps of PCR?
Denaturation, annealing, elongation
