I. Introduction. 1  The petroleum industry began with the successful drilling of the first commercial oil well in 1859, and the opening of the first refinery two years later to process the crude into kerosene.
Trisomy 21â More than 90% of Down syndrome cases are caused by trisomy 21. An extra chromosome (chromosome 21) originates in the development of either the sperm or the egg. When the egg and the sperm unite to form the fertilized egg, three (rather than two) chromosomes 21 are present.
Scientists have successfully turned off the chromosome defect that causes Down syndrome. Down syndrome, also called Trisomy 21, is a genetic condition in which a person has three copies of chromosome 21, resulting in 47 chromosomes instead of 46. It is one of the most common causes of human birth defects. According to the Centers for Disease Control and Prevention, Down syndrome had an incidence rate of 11.8 babies per 10,000 live births from 1999 to 2003.