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What is a genome

the entire DNA content of an organism or cell


what is an exome

the regions of the genome that code for proteins


what is genetic linkage

a measure of how resistant to recombinant a genetic marker and phenotype are


whats does genetic linkage detect

the chromosonal location of diseased genes


what is linkage

tendancy for genes and other genetic markers to be inherited together because of their location near one another on the same chromosome


what is a genetic marker

segment of DNA with an idenitfied physical location on a chromosome whose inheritence can be followed


what does a LOD score show

whether two loci lie near each other and are likely to be inherited together


when is trio analysis used

in diseases where no explaniation can be given
rare and unknown


how does trio analysis work

whole exome is sequenced
looks at approx 20,000 genes, first those genes known to be related then all genes
look for variants and compare against parents


whats is GWAS

an observational study, idenitfy over expressed SNPs in diseased patients


what is the benefit of GWAS

helps understand diseased mechanisms
understand development
identify those at risk


why is whole genome sequencing good

allows you to look at one change e.g deletion


how does GWAS work

we have the geome sequence for over 10,000 SNPs
coat chip with single stranded DNA containing SNPs
hybridise labelled gDNA from individuals
locate genes by showing up on chip


describe a GWAS case control study

purify DNA from 1000s of individuals
map using SNPs chips to identify
looks for overrepersentaion of SNPs in pateints
if lots of people have that genetic difference then it is near that gene
anaylse on computers and mark out genes that have over representaion


what is a biobank

people donate tissue samples
all sorts of varaiables are measured over the years
prospective cohort study


what is mendelian randomisation

determins causality from observations
our genotype is randomly assigned at birth
not influenced by cofounding factors


what are SNPs

A single-nucleotide polymorphism (SNP) is a DNA sequence variation occurring when a single nucleotide adenine (A), thymine (T), cytosine (C), or guanine (G) in the genome (or other shared sequence) differs between members of a species or paired chromosomes in an individual.
They can act as biological markers, helping scientists locate genes that are associated with disease.