Final answer:
The first complete DNA sequence of a non-viral, free-living organism was for Haemophilus influenzae, done by Craig Venter. This was a significant step forward after Fred Sanger sequenced the first genome, a virus. Genome annotation has greatly aided molecular biology research.
Step-by-step explanation:
The first complete DNA sequence of a non-viral, free-living organism was obtained for the bacterium Haemophilus influenzae. This groundbreaking work was accomplished by Craig Venter in the 1980s. While Fred Sanger was responsible for sequencing the first genome, which was that of a viral genome (bacteriophage fx174), the sequencing of Haemophilus influenzae represented a significant advancement in genomics as it was the first genome sequencing of a free-living organism. Sequencing the genomes of model organisms, such as Escherichia coli and the yeast Saccharomyces cerevisiae, has been imperative for basic research. This is because the data gleaned from these model organisms can be applied to genetically similar organisms. Importantly, the process of genome annotation, which involves attaching biological information to gene sequences, has been invaluable for molecular biology research including the design of PCR primers and RNA targets.