You need to ascertain few things first. The primers you are using are meant to amplify full length or partial gene. If the primers are designed to amplify partial gene, then what is the expected band size. It is quite possible that all the primers are amplifying a similar size of product.

Hi Mohamed

Your query seems slightly incomplete.......'all bands are same' in what sense? Have you checked them on agarose gel....kindly pay attention to the following points...

1) You may have designed different primers for the three genes.....do these primers give same length product....check this out....if the product length is same or very similar you may not be able to see them as 'different' on agarose gel (their separation will also depend upon the concentration you have used...if you had done this on gel).

2) keeping above point in mind ....see that the same sized bands (even if they are) on a gel...does not mean they are same sequence

3) Have you compared the PCR products on the gel along with the marker.....are they coming in the expected size range.......up load a photograph of the gel...it will be also clear to us

4) and if you have not compared them with a DNA marker....you may just be looking at the primer dimers..

5) Also...possibility of a contimation cannot be rule out also....

I suggest you consider the above points and compare your products on a concentration of gel that can differentiate them and also with a DNA ladder....

and most important....make sure your cDNA preparation is fine....

bye

This is for mmp-1 and procollagen

My pcr conditions for all genes are the same

If you post your primer sequences I can check the expected product size. It would be easier to interpret your results

Hi Mohamed

I think your reaction look fine...you may have to decrease primer concentrations and as suggested above....by researchers...check your expected sizes of the products...before getting worried why they are same or similar sized.....

bye

Check primers and expected size of product, decrease primer concentration and also check dNTPs conc. The best way to clear all confusion send then for sequencing and see whether its same what you expect.