The majority of bacterial genes are located on the leading strand, and the 
percentage of such genes has a large variation across different bacteria. 
Although some explanations have been proposed, these are at most partial 
explanations as they cover only small percentages of the genes and do not even 
consider the ones biased toward the lagging strand. We have carried out a 
computational study on 725 bacterial genomes, aiming to elucidate other factors 
that may have influenced the strand location of genes in a bacterium. Our 
analyses suggest that (i) genes of some functional categories such as ribosome 
have higher preferences to be on the leading strands; (ii) genes of some 
functional categories such as transcription factor have higher preferences on 
the lagging strands; (iii) there is a balancing force that tends to keep genes 
from all moving to the leading and more efficient strand and (iv) the percentage 
of leading-strand genes in an bacterium can be accurately explained based on the 
numbers of genes in the functional categories outlined in (i) and (ii), genome 
size and gene density, indicating that these numbers implicitly contain the 
information about the percentage of genes on the leading versus lagging strand 
in a genome.