developmental genetics Flashcards
what is forward genetics?
The process of finding what gene is responsible for a particular phenotype/mutated phenotype
What is reverse genetics?
Where you disrupt a gene to try and find what phenotype/mutant phenotype is caused by that gene.
What is an amorphic mutation?
Where there is complete loss of function of a gene.
What does haplosufficient mean?
When a single allelic recessive mutation is seen in the phenotype
What is a haploinsufficient mutation?
Where one wild-type copy of a gene is not sufficient for normal function
What is a dominant-negative mutation?
ANTIMORPHIC- where the mutant copy produces a product that interferes with wild-type function.
What is a hypomorphic mutation?
Partial loss of wild-type function
What is a hypermorphic mutation?
Where there is over expression of a transciption unit - over activity of gene product.
What is produced in an antimorpic mutation?
A competitive inhibitor of gene, so gene lacks activity but still retains co-factor interaction.
What is the aim of a mutagenesis screen?
To identify all genes that play a role in a particular pathway
What is a complementation test used for?
sort mutations into complementation groups, each of which consists of different allelic varients (mutations) of a gene.
How does ionizing radiation cause mutations?
breaks phophodiester bonds in DNA.
How do alkylating agents cause muTations?
(EMS ENU) add alkyl groups to bases - changes base pairing properties. (POINT MUTATIONS)
Give the steps of a mutagenesis screen?
1) Treat adult males with a mutagen (G0)
2) Cross mutant males with wild-type females which produces F1 progeny (heterozygous for different mutations)
3) Cross F1 progeny with wild-type which will produce F2 progeny that will be heterozygous for same mutation
4) do sibling crosses of heterozygotes F2 which will produce F3 progeny - which should be homozygous mutants
5) do a genetic screen for phenotypes of interest
