Dna how does it work

In reality, they will miss some as if they were speed-reading and skipped a letter or word now and again. In the image above, zooming in on the gold bars under chromosome 12 shows such testing gaps. Whole-genome sequencing will not detect large chunks of missing or re-arranged DNA.

It also might miss when a section of DNA has been repeated over and over. Companies such as Veritas Genetics offer this testing for people if prescribed by a doctor. DNA contains a lot of letters. Some sequences make proteins. Others may control how often other DNA sequences are turned on to make those proteins.

Still others might provide instructions for molecules that are not proteins. The exome is that part of a genome that holds protein-coding genes. In the diagram above, the exome appears blue. Exome sequencing generally does not offer information on genetic tweaks that might turn other genes on or off. Many genes play important roles without making proteins at all. Genos and Helix are two companies offer sequence human exomes. Helix also reads some of the DNA next to protein-coding genes. These tests scout for single-letter misspellings sprinkled throughout your genome.

Where most people have an A, for instance, a minority may have a C. Over time, scientists have identified collections of these SNPs and grouped tests to find them together into single tests called SNP chips, or genotyping arrays.

Companies can test hundreds, thousands — even millions — of SNPs at a time with these tests. The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health. What is DNA? From Genetics Home Reference. DNA is a double helix formed by base pairs attached to a sugar-phosphate backbone. What is a gene?

What is a chromosome? For example, if genes coding for proteins involved in cellular growth are mutated, cells may grow and divide out of control. Some cancer-causing mutations can be inherited while others can be acquired through exposure to carcinogens like UV radiation, chemicals, or cigarette smoke.

But not all mutations are bad. Some are harmless while others contribute to our diversity as a species. Changes that occur in more than 1 percent of the population are called polymorphisms. Examples of some polymorphisms are hair and eye color. What factors can influence this?

Something that may play a large role in the DNA damage associated with aging is damage due to free radicals. However, this one mechanism of damage may not be sufficient to explain the aging process. Several factors may also be involved. One theory as to why DNA damage accumulates as we age is based in evolution. Another part of DNA that may be involved in aging are telomeres. Telomeres are stretches of repetitive DNA sequences that are found at the ends of your chromosomes.

Telomere shortening has been associated with the aging process. Perhaps making healthy lifestyle choices like maintaining a healthy weight , managing stress , and not smoking can slow telomere shortening?

This question continues to be of great interest to researchers. The DNA molecule is made up of nucleotides. Each nucleotide contains three different components — a sugar, a phosphate group, and a nitrogen base.

Each sugar in a nucleotide has a nitrogen base attached to it. There are four different types of nitrogen bases found in DNA. They include:. The two strands of DNA form a 3-D structure called a double helix. In a prokaryotic cell, the DNA forms a circular structure.

DNA contains the instructions that are necessary for an organism — you, a bird, or a plant for example — to grow, develop, and reproduce. These instructions are stored within the sequence of nucleotide base pairs. Your cells read this code three bases at a time in order to generate proteins that are essential for growth and survival. The DNA sequence that houses the information to make a protein is called a gene. Each group of three bases corresponds to specific amino acids , which are the building blocks of proteins.

For example, the base pairs T-G-G specify the amino acid tryptophan while the base pairs G-G-C specify the amino acid glycine. This tells the cell not to add any more amino acids to the protein.

Proteins are made up of different combinations of amino acids. When placed together in the correct order, each protein has a unique structure and function within your body.

But what happens in between?