According to the book Biblical interpretation in Judaism and Christianity seen here, quoting Harkavy's own prefatory note to his translation, Harkavy simply copied the common King James bible, as was common to do, while removing Christology from the translation.
Apparently he didn't do such a good job.
Both textual traditions (along with the Samaritan Pentateuch, which has similarities with each) predate Christianity by centuries. Basically, texts, whether religious, or otherwise, present a rainbow-like distribution in terms of variation.
To illustrate this by way of a basic example, for the purpose of clarification:
The difference in genealogies: