genetic variation Flashcards
what are the 3 common types of genetic variants
single nucleotide polymorphisms
micro satellites
copy number variants
what does common mean
we see lots of these types of variants throughout the genome
what is population frequency
the proportion of chromosomes that carry each allele in the population
is every base identical between individuals?
2 people differ in DNA sequence at approx 9 million bps
describe single nucleotide variants SNV
high frequency
many identified in human genome
majority not in exome
generated by mismatch repair during DNA replication
where can SNVs be found
gene
promoter
non coding region
when does polymorphism occur
if minor allele frequency is greater than 1%
what affects whether a variant remains rare
evolutionary forces
what are the 4 evolutionary forces
mutation
gene flow
genetic drift
selection
what is a dinucleotide
two bases repeated
what is the polymerase slippage model
error in DNA replication.
repair mechanism incorporates one extra unit-microsatellitle has expanded
where may micro satellites be
part of 98% not coding for protein
intronic or UTR
intergenic
exonic
what is the simplest type of copy number variation
presence or absence of a gene
individuals genome could contain two, one or zero copies
what causes loci to shift in meiosis
sequence similarity in diff parts of the chromosome
can result in misalignment
what can variant effects be
beneficial
pathogenic
neutral mostly
