1 Nephi 6:1

1  AND now I, Nephi, do not give the genealogy of my fathers in ^athis part of my record; neither at any time shall I give it after upon these ^bplates which I am ^cwriting; for it is given in the record which has been kept by my ^dfather; wherefore, I do not write it in this work.

            -When the 116 pages were lost, we lost a specific genealogy of Lehi, evidently it was not vital and Nephi covered the loss with the more general declaration “it sufficeth … to say that we are descendants of Joseph.”  Even as Nephi was writing, the Lord knew of a situation due to the misjudgments of a prophet many centuries into the future.