 These two definitions of “reproducer” disagree about retroviral reproduction, and what counts as a salient material bond between generations. On one side is the claim that there is no material overlap in the case of retroviral reproduction, and that the key is formal or informational relations (Godfrey-Smith 2009). On the other side, is a view that sees material overlap due to RNA strand hybridization guiding and channeling flows of information (Griesemer 2014, 2016). There is also the introduction of a notion of reproducer that involves only the copying of a property, with no substance overlapping involved (Nanay 2011). Like the second view of reproducer, it appeals to the case of retroviruses having no material overlap (cf. Griesemer 2014, 2016).