Complex sentence: This increase in research would lead to the discovery of further genes related to int1; however, since all those genes had not been activated via proviral integration, it quickly became clear that the int gene nomenclature was no longer adequate.
Split into simpler sentences: This increase in research would lead to the discovery of further genes related to int1. However, since all those genes had not been activated via proviral integration, it quickly became clear that the int gene nomenclature was no longer adequate.