true or false, Protein and DNA markers directly monitor genetic variation in the gene products or the genes
true
how are iso zymes separated
separated on non denaturing gels
what are the properties of non denaturing gels
polyacrylamide
- mobility- size and net charge
- selective detection of bands and activity stain
describe properties of denaturing gels
SDS, polyacrylamide
- protein is denatured, coated with SDS (neg. charge)
- mobility, size
- total protein stain (Coomassie Blue)
what are the characteristics of isozymes
- isolate proteins from tissue where the gene is expressed
- non denaturing polyacrylamide electrophoresis
- stain for protein using activity assay
- mobility differences arise from difference in:
surface charge
overall charge
protein size - over 75% of amino acid substitutions can be seen as changes in mobility
describe protein based markers
- need good activity stain
- relatively few available- much variation missed:
some base changes not cause protein change
some aa changes no cause detectable polymorphism
only genes with easy activity monitored - proteins expressed only in certain tissues at certain times
- some alleles selected for/against
describe DNA based markers
- larger number- all genetic variations can be assesed, including
all changes to genes
variations in non coding regions
variations in regulatory genes - used for any cell type at any time has the same DNA content
what are the applications of DNA markers
Random markers
- DNA fingerprinting
- construction of fine resolution genetic maps
- population and genetic diversity studies
Markers linked to specific loci
- identification of single genes affecting traits
- multigenic trait analyses
what are RFLPs caused by
- base changes that remove sties
- base changes that add sites
- insertions or deletions that change fragment length
what are RFLPs used for
used to identify specific mutations that cause genetic disease
true or false, RFLPs ; linked to disease loci can be used to predict disease
true
what is a single locus marker
- RFLPs (southern blots)
- Microsatellites (PCR)
- SNPs (microarrays)
- one locus at a time, defined location on chromosome
- more expensive to develop, need clones or sequence
- results comparative between individuals and species
- most widely used markers
what are multi locus markers
- minisatellites (southern blots)
- RAPDs (PCR)
- AFLPs (PCR)
- many loci at once
- unknown location on chromosome
- zero development cost, universal probes or primers
- results comparable within species, but not across divergent species
useful for uncharacterised species, eg. ecological studies
