Toronto: Have you heard of Chromosome 16? No, it is not an upcoming science-fiction film but stark reality where a missing copy of a region in Chromosome 16 in the human body can result in a 25-point intelligence quotient (IQ)-drop in the carrier, claim researchers.

Also, an addition of a copy in the same genomic region on chromosome 16 -- known to predispose to autistic spectrum disorders -- results in an approximate 16-point drop in IQ.