Complex sentence: It was based heavily the idea from Bulmer (1971) that regularities existed in the frequencies of alleles that could be determined by electrophoresis (was later determined unfit to analyze electrophoresis alleles).
Split into simpler sentences: It was based heavily on the idea from Bulmer (1971) that regularities existed in the frequencies of alleles. This could be determined by electrophoresis (was later determined unfit to analyze electrophoresis alleles).