Deoxyribonucleic acid (DNA) is a nucleic acid containing the genetic instructions used in the development and functioning of all known living organisms (with the exception of RNA viruses). The DNA segments carrying this genetic information are called genes. Likewise, other DNA sequences have structural purposes, or are involved in regulating the use of this genetic information. Along with RNA and proteins, DNA is one of the three major macromolecules that are essential for all known forms of life.
DNA consists of two long polymers of simple units called nucleotides, with backbones made of sugars and phosphate groups joined by ester bonds. These two strands run in opposite directions to each other and are therefore anti-parallel. Attached to each sugar is one of four types of molecules called nucleobases (informally, bases). It is the sequence of these four nucleobases along the backbone that encodes information. This information is read using the genetic code, which specifies the sequence of the amino acids within proteins. The code is read by copying stretches of DNA into the related nucleic acid RNA in a process called transcription.Scientists have learned that DNA can be changed by environmental and other influences, such as air and water pollution, and these changes could cause significant changes the the plants and animals involved with the DNA. In fact, changes to DNA are believed to be the basis of evolution. Because of the wide spread of pollution, changes to DNA could become a world-wide disaster.
Within cells DNA is organized into long structures called chromosomes. During cell division these chromosomes are duplicated in the process of DNA replication, providing each cell its own complete set of chromosomes. Eukaryotic organisms (animals, plants, fungi, and protists) store most of their DNA inside the cell nucleus and some of their DNA in organelles, such as mitochondria or chloroplasts. In contrast, prokaryotes (bacteria and archaea) store their DNA only in the cytoplasm. Within the chromosomes, chromatin proteins such as histones compact and organize DNA. These compact structures guide the interactions between DNA and other proteins, helping control which parts of the DNA are transcribed.
Here are links to scientific research about DNA contamination.
The DNA encodes the entire genetic information required for building the proteins of the cell. Hence, DNA breaks disrupt the proteins and lead to changes in the cell function. These changes can lead to defects in the control of cellular proliferation resulting in cancer development.
The team tested the human-made, ultrafine particles between 1 and 100 nanometers in size on a human food crop, the radish, and two species of common groundcovers used by grazing animals, perennial and annual ryegrass. This research is part of NIST's work to help characterize the potential environmental, health and safety (EHS) risks of nanomaterials, and develop methods for identifying and measuring them.