DLA 18 Flashcards
how can the size of the triplet repeat be measured
- can measure by gel electrophoresis
- column chromatography
- southern blot
What is G-band genetic testing good for?
looking at whole chromosome changes
very large deletions, duplication’s, and rearrangements
how to prepare G-banding karyotype analysis or for FISH?
- isolation of cells from peripheral blood sample
- culture cells in the presence of phytohemagglutinin to stimulate cell division
- arrest the cells at the metaphase phase of mitosis with colchicine
- cells are swelled in a hypotonic solution and burst onto a microscope slide
- chromosomes are fixed and prepared for staining and visualization
what are the cons of G-banding?
- low resolution
- can always, for sure, determine if their is a problem
- only large changes can be identified
What are the benefits of FISH?
it has a better resolution compared to G-banding
they do not have to be in the metaphase stage
what are the two general types of FISH?
- chromosome specific (FISH)- used for a specific locus
2. chromosome painting (SKY)- whole genome- each chromosome is a different color
What are the cons of FISH
must know what you are looking for
does not detect deletions (sky fish)
What is microarray comparative genomic hybridization (array CGH)
a molecular cytogenetic technique that allows detection of DNA sequence copy number changes throughout the genome in a single hybridization
How does array CGH show mutation?
will glow green if their is a gain in genomic DNA copies
will glow red if loss in genomic DNA copies
yellow = normal
what is not shown in array CGH?
balanced translocations
triplet repeat expansions
SNPs
what techniques show balanced translocations?
both forms of FISH
cons of CGH array?
what is normal?
is the variation significant?
does not have a high dynamic range
What is SNP array?
This analysis involves labeling genomic DNA fragments and allowing them to hybridize to DNA spots
each spot represents various alleles of a gene
What does a + single on a SNP represent?
The presents of a particular SNP within the genome of that particular individual
2 = hetero
1= homo
(get genetic map quickly)
What is the expression array? (cDNA microarray)
- can be used to identify genes that are expressed
2. compare gene expression between cells
