Their study looked for chromosomal deletions and duplications known as copy number variants (CNV) and found that these were present in 16% of the children with ADHD.
Looking at the human genome as a "book of life" they have mapped vast Numbers of variations in letters or short words - but missed much larger deletions and duplications of pages or chapters.
If it is truly difficult to present the original document or physical evidence, then duplications, photographs, copies, or extracts of the original evidence may be admitted.
