Mycoplasma genitalium, colored transmission electron micrograph
(TEM). M. genitalium has the smallest genome (total genetic material) of
all living organisms. Its genome was mapped in 1993, making it the
second complete bacterial genome to be sequenced. In January 2008, a
team at the J. Craig Venter Institute, USA, used this map to make a
synthetic bacterial chromosome, called M. laboratorium, from scratch. A
chromosome is made up of proteins and DNA (deoxyribonucleic acid). DNA
contains sections (genes) that encode the cell's structure and function.
The new chromosome, containing only the genes needed for life, was then
inserted into a M. genitalium bacterium with its genome removed. Having
a different chromosome changes the bacterium's function, making it
different from wild M. genitalium bacteria. Magnification: x43,000 when
printed 10cm wide.