DNA structure DNA consists of molecules called nucleotides. Each nucleotide contains a phosphate group, a sugar group and a nitrogen group. The four nitrogen groups are adenine (a), thymine (t), guanine (g) and cytosine (c). The order of these bases determines the instruction or genetic code of DNA. There are about 3 billion bases in human DNA, more than 99% of which are the same in all people. According to the National Library of Medicine (NLM),
Cool scientific experiment: extracting your DNA chain (Genetic Science Learning Center) is similar to the alphabetical order of the alphabet and can be used to form a word. The nitrogen sequence in the DNA sequence forms a gene that tells cells how to make protein in their language. Another type of nucleic acid, ribonucleic acid, or RNA, converts the genetic information in DNA into protein.
Nucleotides are linked together to form two long chains, and spirals form a structure called double helix. If you think that the double helix structure is a ladder, phosphoric acid and sugar molecules are sides, and bases are steps. The bases on one chain and the bases on the other chain: adenine and thymine, guanine and cytosine.
DNA molecules are very long. In fact, they cannot be integrated into cells without proper packaging. In order to adapt to the inside of cells, DNA tightly curls to form what we call chromosomes. Each chromosome contains a DNA molecule. Humans have 23 pairs of chromosomes, which exist in the nucleus.
Discovery of DNA DNA was first observed by German biochemist Frederich Miescher in 1869. But for many years, researchers did not realize the importance of this molecule. It was not until 1953 that james watson, francis crick, maurice wilkins and rosalind franklin discovered the structure of DNA-a double helix structure-that they realized that it could carry biological information.
Watson, Crick and Wilkins won the 1962 Nobel Prize in Medicine, "because they discovered the molecular structure of nucleic acid and its importance to information transmission in biomaterials." Franklin didn't win the prize, although her work was part of the research. [Related: Unlocking the Human Genome: Six Molecular Milestones]
DNA sequencing DNA sequencing is a technology that enables researchers to determine the base sequence in DNA sequences. This technique can be used to determine the base sequence of genes, chromosomes or the whole genome. According to the report of the National Human Genome Institute, in 2000, researchers completed the first complete sequence of the human genome.
DNA testing A person's DNA contains information about their inheritance, and sometimes it can reveal whether they are at risk of certain diseases. DNA testing or genetic testing is used for various reasons, including diagnosing hereditary diseases, determining whether a person is a carrier of genetic variation (they can pass genetic variation on to their children), and checking whether a person is at risk of hereditary diseases. For example, mutations in BRCA 1 and BRCA2 genes are known to increase the risk of breast cancer and ovarian cancer. Analyzing these genes in genetic tests can reveal whether a person has these mutations.
The results of genetic tests may affect a person's health. These tests are usually provided together with genetic counseling to help individuals understand the results of the tests and the results.
"At present, there are many genetic testing kits in China, but some of them are not reliable. In addition, NBC News reported that people should use these toolkits with caution, because these tests basically give a person's genetic code to strangers.
In the past few years, new research on DNA has brought some interesting and important discoveries. For example, a study published in Science in 20 17 found that random errors in DNA, rather than genetic or environmental factors, accounted for two-thirds of cancer mutations in cells.
Another breakthrough of 20 17 is the first sequencing of Egyptian mummy DNA. Stephen Full, head of the Population Genetics Group of Max Planck Institute of Human History Science, said: "We are very happy to obtain the first batch of genome-wide data of ancient Egyptian mummies. This discovery was published in the 20 17 issue of Nature Newsletter.
The video was also encoded with data, and a short video of bacterial DNA molecules was made on 20 17. DNA is used as the code for every pixel in the movie. The results were published in the journal Nature from 2065438 to July 2007. "The key is not to store videos in bacteria," said Seth shipman, a co-author of the study and a postdoctoral fellow at Harvard Medical School. "We want to turn cells into historians," shipman said in a statement. We imagine a biological memory system, which is much smaller and more widely used than the current technology. As time goes by, it can track many events and contributors to life sciences without interference.
Additional resources
NLM: What is mitochondrial DNA? Florida State University: Mitochondria Washington University: Mitochondria Disorder