ABSTRACT
In 1958 Jerome LeJeune (or a female researcher in his lab, in an alternate telling of origin tales) peered through the microscope at samples of smooth connective tissue taken from three patients with Down's syndrome, and identified the 47th chromosome whose presence spells the existence of that condition. In the late 1960s, several teams of doctors reported identifying the same extra chromosome in amniotic fluid extracted from pregnant women's uteruses, opening up the possibilities of prenatal diagnosis for Down's, and other inherited disabilities.
