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.
The cause of Down syndrome is one of three types of abnormal cell division involving chromosome 21. All three abnormalities result in extra genetic material from chromosome 21, which is responsible for the characteristic features and developmental problems of Down syndrome.
Down Syndrome Mutation. Down Syndrome is caused by a trisomy. Another name for down syndrome is Trisomy 21. When a child receives its chromosomes pairs from their parents and a trisomy occurs...you receive 3 chromosomes instead of the two that are normally in a pair. When this happens on the 21st chromosome, it will most likely result in down syndrome. The mutation is a trisomy.