we've wrote a manuscript applying a computational modelling technique to a field (behavioral ecology) which is not related to our primary research field (neurobiology). This was the result of some year and a half of work, as a parallel project that we took interest upon.
The thing is, the institute to which we're affiliated has nothing to do with the theme of the manuscript, nor we have any published experience in said field.
How much will that matter for acceptance? Do editors take affiliations into consideration? Does it matter which journal (say, Nature cares but PLoS Computational Biology doesn't)?