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 in 1989 by the Voyager 2 probe. The conventional wisdom that Neptune's discovery should be credited to both Adams and Le Verrier has recently been challenged putting in doubt the accounts of Airy, Challis and Adams in 1846.