On the origin of the supernumerary chromosome in autosomal trisomies — with special reference to Down's syndrome

摘要

The differential staining methods for chromosomes have led to the demonstration of more chromosomal polymorphisms. Not rarely, these polymorphisms allow in autosomal trisomies the detection of parental origin of the supernumerary chromosome. In addition, the malsegregation may be ascribed to 1st or 2nd meiotic division in informative families.