Programming the statistical procedures from SAS

Help with right procedures

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Help with right procedures

Hi, All,

I am not a statistician. I would greatly appreciate if some body could give me some suggestions for my following data analysis.

I have an experiment in which 12 mice from 3 genotypes were treated by a drug and followed 3 timepoints (pre-treatment, 48hr, 96hr, and 1wk) after the treatment. I randomly took 6 hairs from each mouse at each timepoint to measure the expressions of one gene in the follicels (e.g., 6 biological replicates per mouse per time point). I am trying to find 1) whether the gene expressions were affected by the drug no matter the mouse genotype is; 2) whether there is an effect of genotype on the drug response. I thought this might be a repeated measurement experiment and tried to use the Proc Mixed with the repeated option (with timepoints as repeated and subjuect=mouseID). Since each mouse at each timepoint have 6 bioligical replicates, I don't know how to handle this replicates in the Proc Mixed. My SAS code is:

Proc Mixed data=mice;
class MouseID Genotype Timepoint;
model GeneExpression = Timepoint; /*or GeneExpression = Genotype;*/
repeated Timepoint / subject=MouseID type=cs;
run;

Is there any thing wrong in the codes? Thanks.
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