Fosmids are similar to cosmids but are based on the bacterial F-plasmid. The cloning vector's limited, as a host (usually E. coli) can only contain one fosmid molecule. Fosmids are 40 kb. Low copy number offers higher stability than comparable high copy number cosmids. Fosmid system may be useful for constructing stable libraries from complex genomes. Fosmid clones were used to help assess the accuracy of the Public Human Genome Sequence.… (More on Fosmid)