Genetic testing Flashcards Preview

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Flashcards in Genetic testing Deck (12):
1

Cytogenetics

Physical structure and composition of chromosomes
Eg. karyotype

2

Molecular cytogenetics

Combination of molecular biology and cytogenetics
Eg. FISH, molecular karyotype

3

Conventional karyotype

Visually analysis whole chromosomes
Detects aneuploidy, large chromosomal imbalances, balanced and unbalanced translocations
10-12 days

4

FISH

Fluorescence In Situ Hybridisation
Detects presence/absence of specific DNA sequences on chromosomes
Fluorescent-labelled DNA probes for specific target

5

CGH

Comparative Genome Hybridisation
Compare DNA (genome) from 2 sources: test and control
Looks at gains/losses of DNA content i.e. difference in amount of genetic material

6

Chromosomal microarray

Uses array based CGH method or SNP arrays
Detects unbalanced chromosome changes

7

Microarray detection

CGH & SNP: copy number abnormality
- microdeletions
- microduplications
- trisomy
- single gene diagnoses (some)
- CGH mosaicism approx 15%

SNP only - copy number neutral with genotype abnormalities
- chimerism
- uniparental disomy
- LCSH (long continuous stretches of homozygosity)
- mosaicism approx 7%

8

Sanger sequencing

Determines exact sequence of bases

9

PCR

Polymerase chain reaction
Used for amplification of sequence of interest

10

Linkage analysis

Indirect test
Based on linkage = genes that are close together are inherited together (chromosome exchange at meiosis)

11

MLPA

Multiplex Ligation-dependent Probe Amplification
Modified PCR amplification
Detects deletions and duplications of any gene
Cannot detect sequence changes or large copy number changes

12

Methylation sensitive MLPA

Can detect methylation ie. parent of origin of sequence of interest
Used for imprinting disorders (Eg. Prader Willi, Angelman, Beckwith Wiedermann)