7.1 2 DNA sequencing Flashcards
Basic principles in all different methods of DNA sequencing
DNA strands chopped into small pieces
double strands separated to single strands
PCR replicates DNA fragments to produce large quantities of material for analysis
Labelled termnator bases are added to strands of DNA
The coloured tags enable the sequence of bases to be read very rapidly by an automated system
Terminator bases
modified version of one of the four nucleotide bases (A,T,G,C) when incoperated into the DNA molecule chain is haltered so no more bases can be added stop dna synthesis e.g at A base. Each terminator has a fluorescent tag in a specific colour
Massively parallel sequencing
work on million DNA fragements at a time
heavily dependent on state of the art computer technology
raw data fed into computer systems that can reassemble genomes
compare all fragments and find areas of overlap
Uses
DNA bar-coding can be used to identify species and investigate evolutionary relationships
DNA sequencing
determine the protein produced from any particular gen
recognize start and stop universally
form base pairs can work out amino acids then proteins
more proteins
then genes by far
complexity in the relationship between the genome and the proteins produced
small number of
diseases that result directly from a mutation of a single gene
can now identify faulty gene see which bases have changed and understand how that is changing the protein how affects symptoms
most non-communicable diseases
not the result of a change in a single gene instead are the result of a number of gene variants that increase the risk e.g coronary heart disease
many cases interaction between genome and the enviroment
can identify
mutations associated and develop new targeted thearpies
computers
give us the capactiy to analyse and compare the genome sequences
gene variants
different versions of genes same meaning as allele
