Cryogenic storage of human tissue. Gloved hands store human tissue in liquid nitrogen for DNA (Deoxyribonucleic Acid) research. A metal box containing tissue samples is seen with the researcher using large forceps to store an individual sample. The storage of such samples in liquid nitrogen (at -196 degrees centigrade) is known as cryogenics. Tissue samples such as umbilical cord and blood cells from relatives are stored. DNA extracted from these cells is used to study the progression of hereditary disorders such as Huntington's chorea or Haemophilia.