Relative expression between controls and subjects

Go to the profile of rima250
Dec 03, 2017
0
3

Dear experts,
As far as I know, the relative expression difference between controls and subjects comes from difference between controls and subjects. In a way, that controls would assign as 0 or 1 and subjects' results varies by over or lower expression compared to fixed control results.I have noticed in some articles which neither of the groups have fixed number. How possible to have e.g. 0.2 or 1.3 fold changes for controls?

3 Comments

Go to the profile of relaxin
relaxin 7 months ago

The fold change is defined as the expression level of experimental/expression level of control. Then the control is set at "1". A 1.3 fold change will be slight increase over control. A 0.2 fold change will be a decrease down to 20% of control.

The control value should not be set to "0", as you cannot divide any number by "0".

Go to the profile of rima250
rima250 7 months ago

My question is: how could the expression for controls less than 1? As we compare subjects to controls, and expression for controls could not be e.g. 0.2.

Go to the profile of relaxin
relaxin 7 months ago

The control is always set to "1". The experimental is expressed as fold over control. A value of "0.2" is 1/5 of control, while a value of "2" is 2-fold over control. You may read the details of calculation in the link below:

https://bitesizebio.com/29322/methods-relative-quantification-qpcr-data/