The function of individual genes Flashcards
(30 cards)
how do we get information about the function of a gene from its phenotype
by studying organisms that are naturally variant for a particular gene - we can study what that gene might do
how do we get information about the function of a gene from its phenotype if there are no natural variations that exist
we make our own variations and by studying both these types of variants we can learn how particular variations lead to phenotypic change
what is natural variation
naturally occurring differences in genetic sequences within a species, arising from mutations that have been maintained through natural selection
what are the 2 types of genetic techniques that can be used to find the out the function of a gene
- functional molecular genetics
- model organisms can be used to make mutants
what are 3 types of approaches regarding functional molecular genetics
- genetic screen
- transgenesis/genetic engineering
- targeted mutation/ gene knockout/ reverse genetics
how does the approach of a genetic screen work in identifying the function of a gene
increase the rate of random mutation - select for a phenotype of interest and sequence the genome to identify the mutation
how does the approach of a transgenesis/genetic engineering work in identifying the function of a gene
taking a gene you are interested in, copy it and insert it into another organism
how does the approach of targeted mutation/ gene knockout/ reverse genetics work in identifying the function of a gene
by deliberately breaking a gene to see what happens
what are model organisms
organisms that can be easily raised in a controlled environment and are easily to manipulate genetically
what is transgenesis
engineering a multicellular organism by adding in foreign DNA
what can we use transgenic DNA for
- understand how gene work
- engineer recombinant proteins (synthetic biology)
- gene therapy approaches
what is a transgene
a gene that has been transferred from one organism to another
how can we damage/modify the genes we are interested in
by genetically modifying an organism or cell line
how are we able to work out what a gene normally does through ‘breaking a gene’
by examining the organism or its offspring after breaking the specific gene
what is CRISPR - Cas9
a type of target mutation where a clustered regularly interspaced short palindromic repeats is used in association with CRISPR associated protein 9
where did CRISPR evolve from
in bacteria as an antiviral defense
what do you have to mix together in order to start your CRISPR targeted mutation
- Decide which gene you wish to mutate.
- Design a short “guide” RNA that only binds to your gene of interest.
how does CRISPR work
Cas9 enters the _______ and finds the _________ in
the genome that matches guide RNA
nucleus
target sequence
how does CRISPR work
Cas9 makes _________ in DNA at target site
a double stranded break
how does CRISPR work
In the absence of a template,_________ try to patch up the cut. This often results in errors as there is no template to read from.
DNA repair enzymes
how does CRISPR work
Small _____are created at the target site, the gene is potentially, ______or ______
InDels
disrupted
mutated
how does CRISPR work
If ___________is provided, it is possible to use this to “edit” the DNA sequence at the cut site - “gene editing”
repair template
what is gene editing
alteration of the genetic material of a living organism by inserting, replacing, or deleting a DNA sequence
what do we need to know in order to fix genetic diseases
- we know what causes it
- have a way to correct the defect
- have considered the ethics
