DNA

Main Thing

DNA is the blueprint of life, carrying genetic instructions for all known organisms and many viruses.

DNA is composed of four nucleotides: adenine, thymine, guanine, and cytosine, which pair up to form the double helix structure. Adenine pairs with thymine, and guanine with cytosine. The sequence of these pairs forms the genetic code, which is transcribed into RNA and then translated into proteins. These proteins perform various functions in the body. A person's DNA is a combination of DNA from their father and mother, making each individual unique.

For example, your DNA contains instructions for your physical appearance and some personality traits, inherited from your parents.

Terms

• Nucleotide – A building block of DNA and RNA consisting of a base (adenine, thymine, guanine, cytosine in DNA; adenine, uracil, guanine, cytosine in RNA), a sugar molecule, and a phosphate group. Example: The sequence of nucleotides in DNA determines genetic information.

• Double helix – The structure formed by double-stranded molecules of nucleic acids such as DNA. Example: The double helix of DNA is like a twisted ladder, where the steps are made of paired nucleotides.

• Genetic code – The set of rules used by living cells to translate information encoded within genetic material (DNA or mRNA sequences) into proteins. Example: The genetic code is read in sets of three nucleotides, called codons, each of which specifies a particular amino acid.

• RNA (Ribonucleic Acid) – A nucleic acid present in all living cells. Its principal role is to act as a messenger carrying instructions from DNA for controlling the synthesis of proteins. Example: mRNA is a type of RNA that copies the genetic instructions from DNA in the nucleus and carries them to the ribosome.

• Proteins – Large, complex molecules that play many critical roles in the body. They do most of the work in cells and are required for the structure, function, and regulation of the body's tissues and organs. Example: Enzymes are proteins that speed up chemical reactions in the body.

An analogy

DNA can be thought of as a cookbook that contains all the recipes (genes) needed to make the proteins that run the body's functions. Just as a cookbook is passed down through generations, DNA is inherited from our parents.

A main misconception

Many people think that DNA is the sole determinant of their traits and health. However, environmental factors and lifestyle choices also play a significant role. Example: While DNA may predispose someone to a certain condition, diet, exercise, and other environmental factors can influence whether this condition develops.

The history

1. 1869 - Friedrich Miescher discovers nucleic acids, the chemical substance of DNA.

2. 1953 - James Watson and Francis Crick describe the double helix structure of DNA.

3. 2000 - The Human Genome Project, an international research effort, successfully maps and sequences the human DNA.

4. 2012 - Introduction of CRISPR-Cas9, a revolutionary gene-editing technology that allows for precise, directed changes to genomic DNA.

5. 2020s - Development and application of gene therapy techniques, using DNA to treat or prevent diseases by correcting genetic disorders.

"We have discovered the secret of life." - Francis Crick, co-discoverer of the structure of DNA, famous for his work in understanding the genetic code and its implications for biology and medicine.

Three cases how to use it right now

1. Genetic Testing for Disease Risk: Individuals can undergo genetic testing to determine their risk for certain diseases known to have a genetic component, such as breast cancer or cystic fibrosis.

2. Personalized Medicine: Doctors can use a patient's genetic information to prescribe medications that are more effective based on their DNA, reducing the risk of adverse reactions.

3. Ancestry and Genealogy: People can use DNA testing services to learn about their heritage and find relatives based on shared DNA.

Interesting facts

• Every human shares approximately 99.9% of their DNA with every other human.

• The human body contains about 2 meters of DNA, tightly packed into the nucleus of each cell.

• If unwound and linked together, the DNA in all the cells of an individual's body would stretch approximately twice the diameter of the Solar System.

• More than half of your DNA is not human but made up of what is known as "junk DNA" from ancient viruses and other organisms.

• Identical twins have almost identical DNA, but small mutations and environmental factors can cause differences in their appearance.