Inheritance Patterns Flashcards
what is a silence mutation?
the change of one base pair that does not change amino acid sequence, but may have subtle epigenetic effects
what is a missense mutation?
changes amino acid sequence and can be deleterious
what is a nonsense mutation?
mutation that leads to a premature stop codon and a truncated protein product, considered deleterious
what is a frameshift mutation?
mutation caused by an insertion or deletion of 1-2 bps leading to either changes in AA sequence or unmasking a stop codon leading to a truncated product, always deleterious
what is a triple repeat expansion?
DNA polymerase slips and adds a repeat of 3 base pairs (often CAG) expansions increase from generation to generation and can be deleterious at a certain length
what is a genetic locus?
specific position or location on a chromosome
what is an allele?
one of the alternative versions of a DNA nucleotide sequence that may be at a given chromosomal locus
characterize autosomal dominant inheritance
males/females equally affected males/females equally capable of transmission heterozygous 50% prob of passing on usually gain of function
characterize autosomal recessive inheritance
males/females equally affected males/females equally capable of transmission homozygous 25% prob of passing on usually loss of function
characterize X linked dominant inheritance
males/females equally affected
less severe phenotype in females due to X-inactivation
pedigree would look like autosomal dom without male to male transmission
characterize X linked recessive inheritance
mostly males affected
all daughters of affected males are carriers
no male to male transmission
what is penetrance?
when a characteristic presents in a patient
what can lead to non-penetrance?
modifier genes
what is variable expressivity?
expressing different symptoms with the same syndrome
