Biology 11th Edition by Cecie Starr ,Ralph Taggart

تمرين 5

Neurofibromatosis is a human autosomal dominant disorder caused by mutations in the gene. It is characterized by the formation of soft, fibrous tumors in the peripheral nervous system and skin as well as abnormalities in muscles, bones, and internal organs
Because the mutant allele is dominant, an affected child usually has an affected parent. Yet in 1991, scientists reported that a boy developed neurofibromatosis even though his parents did not. When they examined both copies of the boys NF1 gene, they found that the gene on the chromosome he inherited from his father contained a transposon. Neither father nor mother had a transposon in any of the copies of their genes. Explain the cause of neurofibromatosis in the boy and how it arose.