genetic technologies Flashcards
what is the genome
all the genetic info in an organism or cell
how is the genome sequenced
cutting the DNA into fragments which are sequenced and them put back into the correct order to give the whole genome
what are genome projects
use technology to determine the complete sequence of bases that make up the DNA of an organism
how can sequenced genomes be used in biology
-compare with particular species to highlight disease risk or identify mutations which cause disease - so can gte early diagnosis and treatment
-comparision of genomes between speceis can be used to explain the evolutionary relationships between species and used to build phylogenetic trees
what is bioinformatics
science of collecting and analysing complex biological data such as genomes
what is the proteome
sequence of protiens coded for by the DNA base sequence in the genome at a given time
how can the proteome be determined
by sequeceing the genome
why is finding the genome of prokaryotes easier than eukaryotes
-only have one circular length of DNA - cDNA
-no non-coding regions
how has sequencing the proteome advance medicine
-produce vaccines faster
-monitor mutations
-nonitor variations as the pathogen evolves
-idnetify antibiotic resisitance mechanisms
why is eukaryote genome more difficult to sequence
-has introns which need to be removed
-these are non-coding - ie junk DNA or regulatory genes (switch on/off coding regions)
-make up 98.5% of DNA
what was the human genome project
In the 1980s Cambridge scientists had been working on sequencing the genome of a nematode. As they progressed they realised that the technology used in this research could be applied to the human genome
The Human Genome Project (HGP) began in 1990 as an international, collaborative research programme
It was publicly funded so that there would be no commercial interests or influence
DNA samples were taken from multiple people around the world, sequenced and used to create a reference genome
Laboratories around the globe were responsible for sequencing different sections of specific chromosomes
It was decided that the data created from the project would be made publicly available
As a result, the data can be shared rapidly between researchers
The information discovered could also be used by any researcher and so maximised for human benefit
By 2003 the human genome had been sequenced to 99.9% accuracy
The finished genome was over 3 billion base pairs long but contained only about 25,000 genes
This was much less than expected
Following the success of sequencing the human genome scientists have now moved onto sequencing the human proteome
The proteome is all of the proteins that can be produced by a cell
Although there are roughly 25,000 genes within the genome there are many more proteins within the proteome. This may is due to processes such as alternative splicing and post-translational modification
There is also work being done on the human epigenome
These are the inherited changes in DNA that do not involve a change in DNA base sequence
what is DNA sequencing
process of determining the sequence of nucleotides in a piece of DNA
what was Sangers technique to sequence DNA
-1977
-very basic - used radioactive bases as the stop base
-then X-ray and view by hand
-more complicated and time consuming
what is the modern process of Sanger sequenceing
-primer binds to the DNA
-DNA polymerase can make the new DNA by adding nucleotides to the growing chain
-this happens unitl by chance it add a coloured dideoxy nucleotide - meaning it lacks a OH
-this is labbelled as the final positon
-fragments are run through a matrix calld gel electrophoresis which sperates the fragments by size
-short fragments run quickly, long fragments more slowly
-exposed to laser allowing the colours to be detected - so allowing the last nucleotide in the chain to be detected
-from the colurs of dye emitied by the chain terminating nucleotide, the orginal sequence of DNA can build up one nucleotide at a time
how has DNA sequencing changed
-made cheaper
-more cost-effective
-large scale
-faster
