lecture 25 - function of individual genes Flashcards
What are the 3 key functional molecular genetic techniques?
Genetic screen, transgenesis/genetic engineering, target mutation
What is a genetic screen?
A method to increase the rate of random mutation, select for a phenotype of interest and sequence the genome to identify the mutation
What is trans genesis/genetic engineering?
Taking a gene of interest, copying it and inserting it into another organism
What is target mutation?
Deliberately breaking a particular gene to see what the effect is in the phenotype.
What are model organisms, in terms of genetic research?
Organisms that can be easily raised and genetically manipulated to study genetics.
What is the process of transgenesis?
Add foreign DNA to a zygote nucleus by inserting a trans gene (target gene + regulatory sequence)
What is a transgene?
A sequence of a target gene + a regulatory sequence that is inserted during transgenesis.
What is CRISPR-Cas9?
A technology that enables the removal, addition or altering of a genome
What does CRISPR stand for?
Clustered Regulatory Interspaced Short Palindromic Repeats
What is Cas9?
CRISPR associated protein 9
What is the structure and function of Cas9?
It is a protein that has active sites that can cut DNA at a particular target gene.
How is a Cas9-guide RNA complex formed?
When guide RNA with a sequence complementary to the Cas9 bind to the active site of a Cas9 protein
What is the function of Cas9-guide RNA complexes?
The guide RNA is a specific RNA sequence that recognizes the target DNA region of interest and directs the Cas nuclease there for editing.
They are added to the nuclei of cells of interest where they find, bind to and remove target sequences of DNA.
What occurs to the DNA when the Cas9-guide RNA complex has removed the target gene?
DNA repair enzymes will try to patch up the cut section, but there will usually be errors, e.g. InDels or mutations. Thus a new sequence can be created.
What is somatic gene therapy?
A therapy that targets affected somatic cells/organs and delivers functional copies of faulty genes or removes parts of faulty genes to restore function.
