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.
Beyond the Planets - the discovery of Pluto. Neptune was discovered in 1846, ostensibly as a result of calculations to explain deviations in the position of Uranus, but substantial luck was involved. These objects complete the list of real planets.