L9

Question 1

true or false, Protein and DNA markers directly monitor genetic variation in the gene products or the genes

Answer 1

true

Question 2

how are iso zymes separated

Answer 2

separated on non denaturing gels

Question 3

what are the properties of non denaturing gels

Answer 3

polyacrylamide

• mobility- size and net charge
• selective detection of bands and activity stain

Question 4

describe properties of denaturing gels

Answer 4

SDS, polyacrylamide

• protein is denatured, coated with SDS (neg. charge)
• mobility, size
• total protein stain (Coomassie Blue)

Question 5

what are the characteristics of isozymes

Answer 5

• 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

Question 6

describe protein based markers

Answer 6

• 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

Question 7

describe DNA based markers

Answer 7

• 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

Question 8

what are the applications of DNA markers

Answer 8

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

Question 9

what are RFLPs caused by

Answer 9

• base changes that remove sties
• base changes that add sites
• insertions or deletions that change fragment length

Question 10

what are RFLPs used for

Answer 10

used to identify specific mutations that cause genetic disease

Question 11

true or false, RFLPs ; linked to disease loci can be used to predict disease

Answer 11

true

Question 12

what is a single locus marker

Answer 12

• 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

Question 13

what are multi locus markers

Answer 13

• 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