Milestones in genomics – first bacterial genome sequenced Which bacterial species had its complete genome sequenced first using whole-genome shotgun sequencing?

Introduction / Context:
The first complete bacterial genome marked a turning point in genomics, enabling comparative studies, pathogen biology insights, and accelerated gene discovery. Recognizing this milestone provides context for modern sequencing technologies and microbial systems biology.

Given Data / Assumptions:

• Question asks for the first fully sequenced bacterial genome.
• Approach used: whole-genome shotgun sequencing.
• Several candidate species are listed, many sequenced later.

Concept / Approach:
Haemophilus influenzae Rd (strain KW20) was published in 1995 as the first complete bacterial genome, using whole-genome shotgun assembly. This achievement demonstrated feasibility for larger genomes and catalyzed the genomics era for diverse microbes.

Step-by-Step Solution:
Recall key historical date: 1995.Link to species: H. influenzae Rd.Select that species from the options.

Verification / Alternative check:
Subsequent early genomes included Mycoplasma genitalium and Escherichia coli K-12, but these were published after the H. influenzae milestone.

Why Other Options Are Wrong:

• E. coli, B. subtilis, S. pneumoniae, S. thermophilus: sequenced later than 1995.

Common Pitfalls:
Confusing first “model” genome (E. coli) with first “completed” genome; model status does not equal earliest sequencing completion.

Final Answer:
Haemophilus influenzae.