Jarom's reporting of his charge concerning the plates is interesting, for both Nephi and Jacob the charge was to maintain the sacred things to the people. Here, however the charge is just to maintain the genealogy. A similar charge marks the transition between Jarom and his son Omni (Omni 1:1). What makes this charge most unusual is that neither Jarom nor Omni (nor Jacob and only minimally Nephi) contain a genealogy. Only in the mention of his parentage does Jarom provide genealogical information. How may we explain the absence of the one thing that the authors indicate is their prime instruction?
Once again we must fall back onto speculation, for we have only this evidence of the command without the expected fulfillment to go on. The repetition of the charge, and the equally absent expected fulfillment of that charge in Omni suggests that perhaps both Jarom and Omni are understanding "genealogy" in a much different context that we might expect from the modern use of the word, and indeed the Biblical examples.
The evidence of what is recorded suggests that the term is being used to cover what we might term "religious history." Starting with Nephi, the small plates have contained elements of history colored by the overriding religious importance of the historical events. This approach to recording on the small plates does appear to have continued through Jarom and Omni, with gross historical events placed in the context of the righteousness of the people. Thus a working hypothesis is that the word "genealogy" in Jarom and Omni might be better rendered "religious or sacred history."
The origins of the term genealogy have to do with beginnings (and therefore begettings) as well as the linking of such information through time. Certainly the chronological ordering of a genealogy fits with the concept of a history, and the probable sacred nature attached to particular kin might be the link by which these ideas were melded.