Konstantin,
sorry for late response. "distribution map" is indeed a particular alignment of reads to the genome but I'd like to add that it should be possible to visualize this alignment as an image something like this one:
http://www.nature.com/nmeth/journal/v6/n4/fig_tab/nmeth.f.247_F2.html Quote:What is the "sample" exactly? Is it a part of the "distribution map" or is it a stand alone sequence?
by sample I mean a sequencing readout (i.e. all aligned reads) for each individual ChIP DNA (= each individual antibody used in the experiment). One experiment often includes more than one sample (more than one antibody) to enable identification of specific binding sites, see below.
Quote:What do you mean mean by "distribution map between two samples"?
this means that the software should identify reads which are in one sample but not in the other. Suppose, you're looking for the binding sites of FOXA3 protein, as on the image I refereed above, and use mouse monoclonal antibody to perform ChIP. In this case you may need to carry out additional ChIP using another mouse monoclonal antibody which does not recognize anything in human cells. This can be, for example, antibody raised against jellyfish protein GFP.
Sequencing of both samples will return some reads because some non-specific binding always takes place. To account for this you would need to compare the reads from FOXA3 ChIP with the reads from GFP ChIP. Reads that will be found only in FOXA3 ChIP but not in GFP ChIP are specific for FOXA3 protein. Reads that are founds in both FOXA3 and GFP ChIP are most likely to originate from non-specific binding mentioned above.