The average human body is made up of around 37.2 trillion cells and most human cells contain tightly coiled DNA strands. DNA is used as a blueprint in the replication and functioning of cells. It has been estimated that if every single strand of DNA in an average human body was unwound and laid end to end they would stretch over 10 billion miles, or more than double the distance between Earth and Pluto.
The majority of this DNA would come from mitochondria, which are organelles within cells that can reproduce themselves and carry a unique genome. While single mitochondria have much smaller amounts of DNA than a cell nucleus, there can be up to 2000 mitochondria in a single human cell.
More about DNA:
- Not all human cells contain DNA. Red blood cells, for example, lack a cell nucleus altogether and are produced in the bone marrow.
- It has been estimated that around 8% of human DNA originates from retroviruses that inserted themselves into our genetic code over millions of years of evolution.
- Almost 5,000 strands of DNA would have to be laid side by side to compare with the width of a single human hair.