September 04

DNA Image Credit: National Human Genome Research Institute

Today in Science

National DNA, Genomics, & Stem Cell Education Month

September is National DNA, Genomics, & Stem Cell Education Month.

The twisting double-helix of deoxyribonucleic acid (DNA) is the building block of all living things. Specific, small portions of DNA are called genes, which contain the instructions for building the proteins that run our bodies, such as determining whether we are male or female or if we have blue eyes or brown. Genes are bundled into chromosomes, of which humans have 23 pairs.

A person contains two copies of each gene, one inherited from each parent (via the sperm and egg that combined to make them). This means that genes carry pieces of information from one generation to the next and explain why a history of heart disease runs in families or why parents who can't roll their tongues can have children who can't either. The study of individual genes and heredity is called genetics.

Each organism, be it a human, a chicken, or an anthrax spore, has a specific and complete set of DNA, which is its genome. The first complete genome, for a bacteriophage, was mapped in 1977. Scientists have mapped nearly 200 eukaryotic genomes (in addition to hundreds of archaea and thousands of bacteria) and are still at work mapping out genomes for lots of other organisms. The study of genomes and how genes interact as a group is known as genomics.

Cells are the basic building blocks of living things, and the human body contains trillions of them. Each cell contains a copy of the person's genetic information, which governs the cell's growth, behavior, and reproduction. Most cells evolve into a single, specialized purpose—blood cells, skin cells, liver cells, etc.—and these specialized cells can only grow more of the same type of cell. A skin cell can't, for instance, divide and change into a blood cell. However, certain cells, called stem cells, are not specialized and have the potential to, using the information from the chromosomes found in the cell's nucleus, evolve into different types of cells. Stem cells can be used to treat some diseases, and their potential continues to be explored by scientists.

Check out some Science NetLinks resources on DNA, stem cells, and genomics:

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