We consider the auto-regulation of a single gene having one, two or four copies. 
In eukaryotic cells, in which the number of mRNA and protein molecules is large, 
the stochastic effects result mainly from the intermittent character of the gene activity. 
We show that the number of gene copies strongly influences the gene autoregulation. 
We found that in the case of negative autoregulation the behavior of one-gene-copy system 
resembles  the  behavior  of  two-gene-copy  system.  However in the case of positive 
autoregulation the one-gene-copy system respond differently to two-gene-copy system. 
This implies that the consequences of gene copy knockout could be potentially more serious 
for positively regulated genes.