In people with chronic myelogenous leukemia, the chromosomes in the blood cells swap sections with each other. A section of chromosome 9 switches places with a section of chromosome 22, creating an extra-short chromosome 22 and an extra-long chromosome 9.
Discovered on September 23, 1846, by John Couch Adams. Neptune was the first planet found by mathematical prediction rather than by observation. Unexpected changes in the orbit of Uranus led astronomers to deduce that its orbit was subject to gravitational perturbation by an unknown planet.
Neptune's largest moon, Triton, was discovered at the same time as the planet. Another satellite, Nereid, wasn't found until 1949. The other six were spotted by Voyager II during its flyby in 1989. A lot of research has been done on Triton, and there is evidence that life may have existed there at one time.