10.3 Flashcards
what are the two types of mutations (in terms of transmission?
somatic mutations - not transmitted
germ-line mutations - may be transmitted to ~50% of offspring
what are the classifications of point mutations based on aa’s?
silent/synonymous - no change
missense/nonsynonymous - 1 aa changes
nonsense - stop codon
what are the classifications of point mutations based on affect on sequence?
indels cause frameshifts that alter reading frames (missense or nonsense) - except when they occur in groups of 3
indels outside of reading frames have no effect
what are the classifications of mutations based on functional phenotype?
loss-of-function - recessive inheritence
gene-of-function (new/wrong gene product) - dominant inheritence
neutral
what are transitions vs transversions?
transitions - purine/pyrimimide swap
transversions - purine/pyrimimide stay the same
do transition or transversion mutations happen more often?
transitions
what are forward vs reverse mutations?
forward alters wild phenotype
reverse changes mutant back to wild phenotype
what are suppressor mutations?
mutation that suppresses a previous mutation
what are the two types of suppressor mutations?
intragenic (same gene)
intergenic (diff gene)
how do mutations happen?
spontaneously or induced
what are the three types of spontaneous mutations?
tautomeric shifts (of bases) during DNA rep
DNA strand-slippage during DNA rep
misalingment of homo chromosomes during crossing over (recomp) at meiosis I
what are tautomeric shifts?
small chemical changes in bases that change which base they can bind to
what is DNA slippage?
strands slip into small loops which results in adding/leaving out a nucleotide
what are mutagens?
agents that cause mutations:
radiation or chemical mutagens
what is ionizing radiation?
dislodges electrons to cause free radicals/ions that alter base structure and break phosphodiester bonds
