I'm analyzing the results of SYBR green realtime PCR, but I had difficulty in interpreting the results of one of the genes tested..
As shown below, there was no gene expression in the control group.
However, gene expression was identified in one of the experimental groups that received the specific stimulus.
In this case, how can I measure the ddCt value of sample1??
Can I calculate ddCt without Ct value of control?
I hope someone give me the clear answer.
Thanks in advance.
cf)
'0' means no expression
Reference gene (RG)
Gene of interest (GOI)
No, you can not calculate deldelCT for you sample if you don't have zero or no value in your control sample. This method is the relative fold change, so both treatments need to have some values.
In order to calculate the fold change, you basically need to use the formula
2^(- delta delta CT). Delta delta Ct equals delta Ct for the treated (experiment) sample minus delta Ct for the untreated (control) sample. Delta Ct for each sample is the Ct for the gene of interest minus the Ct value for the internal control (a housekeeping gene with a known and constant expression).
So in order to perform the analysis, you need at least four ct values: for the gene of interest in the treated sample, for the housekeeping gene in the treated sample, for the gene of interest in the untreated sample, and for the housekeeping gene in the untreated sample.
Basically, delta delta Ct = (Ct target gene in treated - Ct housekeeping gene in treated) - (Ct target gene in untreated - Ct housekeeping gene in untreated)
Of course in order to claim a significance you will need many treated and many untreated samples.
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