Off topic:Forward In The Final Report

Question

[Maria Angelica]

Possible Duplicate:
Illumina’s Genome Studio Final Report: forward or top allele?

Allele - forward in the final report corresponds to bottom strand? Why exists equals allele-forward and allele-top in the final report? As follows:

Allele1-Forward Allele2-Forward Allele1-Top Allele2-Top

   A              G      A       G

Thanks