21 Genomes and their Evolution Flashcards
What is genomics?
The study whole sets of genes (genome) and their interactions,
What is bioinformatics?
The application of computational methods to the storage and analysis of biological data.
What is a map of all the genes in an organism called?
A cytogenetic map
What is a cytogenetic map?
A map of the locations of all the genes i.e. the entire genome
What are the basic approaches to sequencing a genome?
The ’Three-stage approach’ and the ‘Whole-genome shotgun approach’
What basic approach did the Human Genome project use to sequence the genome?
The ’Three-stage approach’
What is the ’Three stage’ approach to genome sequencing?
A linkage map is used to determine the location of genetic markers i.e. restriction sites (RFLPs) and other polymorphisms.
Then ‘physical mapping’ which involves the hysical mapping ordering of large over-lapping fragments cloned in YAC and BAC (bacterial artificial chromosome) vectors, followed by ordering of smaller fragments cloned in phage and plasmid vectors.
Finally ‘DNA sequencing’ which is the determination of nucleotide sequence of each small fragment and assembly of the partial sequences into the complete genome sequence
What is YAC?
Yeast Artificial Chromosome (basically just a BAC but from a eukaryotic yeast)
How does the ‘Whole-Genome Shotgun Approach’ sequence a genome?
It basically skips the linkage map and physical mapping stages.
Cut the DNA from many copies of an entire chromosome into overlapping fragments short enough for sequencing. Then clone the fragments in plasmid or phage vectors.
Sequence each fragment i.e. using the dideoxy method
Because the fragments are overlapping their order can be determined using analysis by a computer. Thus the entire genomes sequence can be determined.
What is DNA from a group of species called?
A metagenome
What is a metagenome?
DNA from a group of species that is collected from an environmental sample.
What is metagenomics?
The analysis of a metagenome (collection of DNA from a range of species from an environmental sample)
What is the analysis of a metagenome called?
Metagenomics
What is the point of metagenomics?
With analysis the genomes of the individual species can be isolated.
This means a sample can be taken where many different bacteria species are, such as in the soil, and each individual species can have its genome sequenced.
(this avoids the need to culture specific bacteria from a mixture)
What is ‘reverse genetics’?
A form where the actual genotype is determined (sequenced)
This contrasts with classical genetics where the genotype is inferred from from the phenotype