Complex sentence: Whole genome shotgun sequencing for small (4000 to 7000 basepair) genomes was already in use in 1979 broader application benefited from pairwise end sequencing, known colloquially as "double-barrel shotgun sequencing".
Split into simpler sentences: Whole genome shotgun sequencing for small (4000 to 7000 basepair) genomes was already in use in 1979. Broader application benefited from pairwise end sequencing, known colloquially as "double-barrel shotgun sequencing".