Complex sentence: In that same year he set up the department of genetics, realising that this was no longer feasible due to administrative problems, he instead decided to set up the Population Genetics Laboratory at Hawaii in 1954.
Split into simpler sentences: In that same year, he set up the department of genetics. After realizing that the department was no longer tenable due to administrative problems, he instead decided to set up the Population Genetics Laboratory at Hawaii in 1954.