7 - ALLELIC VARIATION Flashcards
what do dominant mutations do
having a single copy of the mutation gives you the diseased phenotype even though you have a wild type copy
what are the two models for dominance of a mutation
haploinsufficient and dominant negative
what is an example of a dominant negative mutation
p53 alleles in cancer cells function as dominant negative
p53 is a transcription factor that binds DNA as a homotetramer
there is a mutation in the DNA binding domain in one of the two alleles -> protein is still expressed, mutant can still form homotetramer with functional copies
no loss of function, point mutation
however there is no activation of p53 target genes because of that mutation
what is incomplete or partial dominance
dose-determinant
what is codominance and an example
A and B are dominant over O, but codominant with each other
how is dominance classified
often determined by the phenotype we characterize (methods of detection/observation)
how is Hb dominance different for phenotype anemia and for phenotype blood cell shape
how do HbA and HbS express dominance at the protein level
what is an example of a recessive lethal
what are conditional alleles
what are auxotrophs
organisms that lost the ability to synthesize certain substances required for their growth
what is penetrance
what is expressivity
