disease diagnosis molecular biology methods 3

Question 1

what is array hybridisaiton?

Answer 1

it is a method to quantify mRNAs-

this is helpful b/c mechanisms of disease development often result from changes in gene-expression patterns

the gene-expressio profile in cancerous tumours may aid diagnosis of tumour type, predice risk of metastasis, and develop effective treatment strategies

Question 2

what is the method of

array hybridisation?

Answer 2

1. isolate RNA from test and control tissue
2. convert the RNA into cDNA- copy dna using reverse transcriptase
3. label test and control dna with fluorescent tags - each point on array contains oligos for a specific gene, competitive binding of test and control dNA 0
   4.

Question 3

what types of genetic variation can mRNA array hybridisation detect?

Answer 3

mRNA array hybridisation can detect changes in gene expression only - does not detect germline or somatic changes in genetic variaiton

Question 4

what can DNA array hybridisation tell us?

Answer 4

genotypes multiple different specific germline SNPs in a sample

it can tell us the germline genotype of an individual across hundreds of thousands of different SNPs

used to identify carriers for single-gene disorders and to research the genetics of complex traits

Question 5

what types of genetic variation can DNA array hybridisation detect?

Answer 5

can detect germline changes in genetic variation - cannot detect somatic changes

Question 6

what is the next generation DNA sequencing (NGS)?

Answer 6

it sequences DNA - a technique to sequence DNA that is several orders of magnitude more efficient than Sanger sequencing

• it allows us to sequence complete exomes or complete genomes

Question 7

describe the method of next generation sequencing

Answer 7

1) library/sample prepartation - DNA fragmented and adaptors sequences added
2) cluster generation - required so that the DNA to be sequenced is present at sufficient copy number to achieve required signal
3) sequencing - nucleotides in the sequencing reaction are fluorescently labelled and reversibly terminated
4) data analysis - alignment to reference - comparisons to reference identify points of difference

Question 8

what types of genetic variation can NGS DNA sequencing detect?

Answer 8

it can detect germline and somatic changes in genetic variation

small or large scale