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Identifying genes

6 important questions on Identifying genes

Genomic micro architecture

3 bilion bases
A is linked to T
G is linked to C
30 milion bases are SNP's
Found in 0,1% of people

How should we investigate genetic effects?

You want to know the change in trait value, given a change in genotype.
The though experiment is:
We change the genotype of the fertilized egg cell.
We rerun the entire lifecycle.
This is what plant genetics do --> They make 1000 identical plants and change one allele and then look how the now different plants react on the environment.

When you do this, there is still some variation between the plants with the same genetic allele --> This is the environmental variance.

Why 2: Disease prediction

If we know, for each SNP, its effect on disease.
And we emasure SNP's in patients.
We can predict the risk of disease.
Example breast cancer
Some people carry more risk genes than ohter
Having a higher genetic risk might help you to make the decision to remove the breasts before you even have breast cancer.

Polygenic risk score

Measure of genetic predisposition for complex traits and disease risk.
With GWAS you can estimate the genetic effects on a certain characteristic.
Example:

Having an C will give a genetic effect of -0,02
Having a G will give a genetic effect of +0,01
Then the polygenetic score is calculated by looking at the Dna and look at how much A, C, T, G, the DNA containd and multiply this with the genetic effect each letter gives.

Disease prediction PRS

Disease prediction PRS.
- Age is important for predicting outcomes.
o At age 80 the chance of getting CHD is very high for people with a high polygenetic risk score→62%.
o People with this same polygenetic risk score but at a much younger age have a smaller chance of getting CHD.
o The predicted value of polygenetic risk score becomes higher with age. - So, it is better to start early with interventions to prevent disease.
o For psychological disorders it is hard to prevent disease because we do not yet have preventive medicine.

Gwas not the only use of genetics

Non invasive pregnancy testing.
To test the baby on genetic diseases by taking blood from the mother instead of doing a puncture from the amniotic fluid.
In the blood of the mother ther is genetic material from the mother but also from the baby.
This genetic material can be sequenced by GWAS to predict genetic diseases.
Aiding criminal investigation
It used to be that DNA on the scene would only be compared with the suspect. But now they can compare the DNA with relatives and reconstruct the family tree to come to your suspect.

The question on the page originate from the summary of the following study material:

Behavioral genetics | 9781429205771 | Robert Plomin

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