| Organism | Genome Size (bases) | Estimated Genes |
|---|---|---|
| Human (Homo sapiens) | 3.2 billion | 25,000 |
| Laboratory mouse (M. musculus) | 2.5 billion | 24,174 |
| Fruit fly (D. melanogaster) | 165.0 million | 13,600 |
| Mustard weed (A. thaliana) | 120.0 million | 25,498 |
| Roundworm (C. elegans) | 97.0 million | 19,000 |
| Yeast (S. cerevisiae) | 12.1 million | 6,294 |
| Bacterium (E. coli) | 4.6 million | 4,288 |
| Human immunodeficiency virus (HIV) | 9749.0 | 9 |