Genome Sequencing Flashcards
what is a genome?
-the complete DNA sequence on one set of chromosomes in diploid eukaryotic organisms
-all the exons and introns
what is genome sequencing? what is the use of this?
-working out the base sequence in organisms (the order of bases along each chromosome)
-allows for ancestorial links to be found
what is gene mapping? why is it used?
-identifying exactly where particular genes are on chromosomes
-it allows the exact location of defective genes to be found
what were some of the key steps identifying the complete DNA sequence in early times?
-yeast was first eukaryotic organism discovered
-roundworm was the first multicellular organism to be sequenced
-fruit flies and different types of bacteria were then sequenced
-the number of species being sequenced has increase greatly nowadays
-it has now also become faster and cheaper
what was the human genome project? and when did it start and end?
-started in 1990 and ended in 2003
-the project shoed that the human genome is just over 3 billion base pairs in length and contains 21000 genes
other than the length of bases what were some of the other discoveries from the human genome project?
-they found that only 2% of our DNA actually codes for proteins, the rest doesn’t have a specific job
what are microarray trays? what is put in each of these wells?
-they consist of a solid base e.g. glass, which has a gird of thousands of microscopic wells attached
-a different sequence of DNA is added which acts as a DNA probe
what is the advantage of using a microarray tray?
-used to analyse many genes simultaneously
how is the microarray tray used after the different sequences of DNA are placed in the wells? how can the sample been seen?
-mRNA of interest in washed over the tray
-any mRNA in the sample that is complementary to one or more of the DNA sequences will hybridise
-if the mRNA sample contains a probe which is either fluorescent or radioactive the wells containing the hybridised DNA can be seen
how are the different levels of hybridisation shown on the microarray trays?
-by the wells becoming different colours depending on the degree of hybridisation
what are the 3 uses of the microarray tray?
-identify mutations
-SNPs
-provide information on the expression levels of certain genes
how are microarray trays used to investigate the degree of expression of a gene?
-the genes of mRNA used in the sample which are hybridised can be transcribed to make cDNA
-the degree of cDNA can then be used to compare gene expression between different genes or between different patients with certain medical conditions
what are some of the benefits from the Human Genome Project?
-more detailed mapping of genes which helps with more accurate diagnosis
-sections of the DNA can be identified with microarray technology which allows identification of harmful alleles in carriers
-drug development which can be matched the the genomes of the individual, which reduces side effects and allergies
what does pharmacogenetics?
-the development of drugs and medicines to match the genetic profile of individuals
-it is the study of how genetic differences in humans affects how particular drugs are metabolised by the body
how does the development of genome sequencing increase the potential of gene therapy?
-it allows an understanding of the differences between functional and defective genes
how is genetic finger printing used to compared genetic sequences ?
-it is dependent on the differences in repeat DNA sequences e.g. MRSs and SNPs
-different individuals have different numbers of repeat sequences
how does gene sequencing allow the primary structure of proteins to be worked out?
-if a certain sequence of DNA has been mapped between two points then knowledge of the bases between those points allow the amino acid sequence to be seen
what is one consequence of the Human Genome Project?
-it is apparent that we have fewer genes that have more than one type of allele
-in reality most of our genes have two identical alleles
what percentage are humans similar in terms of DNA sequences and what in specific makes us different?
-all humans are 99.9% similar in terms of DNA sequences
-the differences are in the SNPs
what was the Human Map Project and what did it involve? what was the researchers aim?
-involved analysing the genomes of nearly 300 people to map the location of their SNPs
-the researchers aim was to identify a set of genetic markers
how are genome sequencing projects stored?
-in biobanks
how can organisms be enabled to function as model organisms for the study of genetic diseases?
-through the deliberate removal or addition of a gene
what does the term gene knockout mean?
-it is a transgenic organism in which a gene has been removed or made inoperative
what is the general principle of gene knockouts?
the effect of loss of gene function can be modelled in non human living organisms
what animal is involved most in knockout technology and what are the three reasons why?
-mouse
-it is biochemically and physiologically similar to humans
-short life cycle
-can be kept in a lab
what is gene knockin? how is it used?
-is where a particular gene is added
-used to add a defective gene to study in detail a disease progression
