A small sample of blood is obtained from the affected individual and the parents as a source of DNA , the chemical that carries the 'genetic code' of each gene.
(A small sample of blood; is obtained; from the affected individual and the parents as a source of DNA , the chemical) (the chemical; carries; the 'genetic code' of each gene)
A small sample of blood the chemical
is obtained carries
from the affected individual and the parents as a source of DNA , the chemical
the 'genetic code' of each gene