The smaller chromosome is roughly one-third its size. Both are critical to the germ's viability. The pathogen was discovered by Robert Koch in 1883. In humans, it may trigger severe vomiting and diarrhea. Infected persons usually die from the dehydration effects.
Science is aware of several hundred strains - but it is still unknown how they influence each other.
The researchers hope to be able to develop new vaccines and medication using the newfound genetic information. Last year, some 223,000 people contracted cholera. 8,500 of them died.