Gel (see footnote at end for a brief description of gels aimed at non-biologists) splicing is a term that describes the cutting and pasting of images of lanes (where 1 lane = 1 sample) and placing the images of the lanes in a different order or even combining lanes from different gels. A more extreme form is to simply shift the subsection of the lane, corresponding to the probed molecule, from one lane to the next.
This is wrong and it always has been. However, in post publication peer review on PubPeer, it is often defended, particularly for “older” papers, from a decade or more ago. This then raises arguments about what was acceptable then and are we shifting the goalposts of scientific integrity? The matter has even been a “Topic” on PubPeer.
While I agree that space constraints on gels and in publications led to editors requesting the removal of blank lanes (an important point raised by “Unreg” in the above Topic discussion I do not think that this explains the large number of splicing events coming to light. Today I came across a very nice argument by “Peer1” on PubPeer, to which I can find no riposte – the fact that journal editors aided and abetted the practice cannot condone it. This is Peer1’s argument
This has always been the case, be it in the time of the scalpel and the camera or Photoshop.
The same applies to manipulation of any other data, such as spectroscopy or FACS. Think about it this way. You discover a fossil, with some pieces apparently not fitting the jigsaw of your hypothesis. Rather than go back to the field to search for more data, you simply get out the tools and alter the fossil.
Yes, it is hard, slow and painstaking work and always will be. Those who put their fossils together using glue and claim that this is what was found in the field rightly deserve criticism and that their paper be withdrawn, regardless of whether the actual predicted fossil turns out to exist. The one described in the paper never existed, so the paper cannot either.
I do realise that fossils are put back together again, but I think the point being made is that the joins are explicit, whereas hiding the fact that there is a join is wrong.
Gels of agarose and polyacrylamide are used for the analysis of nucleic acids and proteins. On a gel there will be several lanes, each loaded with a different sample. This allows the comparison of biological samples. By using probes to reveal the identify of particular nucleic acids or proteins, gels allow changes in individual molecules to be monitored in complex samples (cells, tissues, even entire model organisms). So immensely powerful, and these techniques have led to important advances in our understanding of biochemistry and cell biology.