Not having access to the journal article, I wonder how much of this can be explained by retroviruses inserting their DNA, which is well established to be inheritable (e.g. when the retrovirus managed to infect sperm or egg in humans).
Retroviruses could be a mechanism for the DNA jump - though we'd have to ask how they got a portion of an host's DNA - or they could be an alternative mechanism which would explain why the surrounding 'junk' DNA is identical without requiring a speculative 'DNA jump', all three fish species could have been infected by the same retrovirus.
Retroviruses could be a mechanism for the DNA jump - though we'd have to ask how they got a portion of an host's DNA - or they could be an alternative mechanism which would explain why the surrounding 'junk' DNA is identical without requiring a speculative 'DNA jump', all three fish species could have been infected by the same retrovirus.