All living beings have genes. They exist throughout the body. Genes are a set of instructions that determine what the organism is like, its appearance, how it survives, and how it behaves in its environment.
Genes are made of a substance called deoxyribonucleic acid, or DNA. They give instructions for a living being to make molecules called proteins.
A geneticist is a person who studies genes and how they can be targeted to improve aspects of life. Genetic engineering can provide a range of benefits for people, for example, increasing the productivity of food plants or preventing diseases in humans.
What are genes?
Genes are responsible for all aspects of life.
Genes are a section of DNA that are in charge of different functions like making proteins. Long strands of DNA with lots of genes make up chromosomes. DNA molecules are found in chromosomes. Chromosomes are located inside of the nucleus of cells.
Each chromosome is one long single molecule of DNA. This DNA contains important genetic information.
Chromosomes have a unique structure, which helps to keep the DNA tightly wrapped around the proteins called histones. If the DNA molecules were not bound by the histones, they would be too long to fit inside of the cell.
Genes vary in complexity. In humans, they range in size from a few hundred DNA bases to more than 2 million bases.
Different living things have different shapes and numbers of chromosomes. Humans have 23 pairs of chromosomes, or a total of 46. A donkey has 31 pairs of chromosomes, a hedgehog has 44, and a fruit fly has just 4.
DNA contains the biological instructions that make each species unique.
DNA is passed from adult organisms to their offspring during reproduction. The building blocks of DNA are called nucleotides. Nucleotides have three parts: A phosphate group, a sugar group and one of four types of nitrogen bases.
What are they made of?
A gene consists of a long combination of four different nucleotide bases, or chemicals. There are many possible combinations.
The four nucleotides are:
Different combinations of the letters ACGT give people different characteristics. For example, a person with the combination ATCGTT may have blue eyes, while somebody with the combination ATCGCT may have brown eyes.
To recap in more detail:
Genes carry the codes ACGT. Each person has thousands of genes. They are like a computer program, and they make the individual what they are.
A gene is a tiny section of a long DNA double helix molecule, which consists of a linear sequence of base pairs. A gene is any section along the DNA with instructions encoded that allow a cell to produce a specific product – usually a protein, such as an enzyme – that triggers one precise action.
DNA is the chemical that appears in strands. Every cell in a person’s body has the same DNA, but each person’s DNA is different. This is what makes each person unique.
DNA is made up of two long-paired strands spiraled into the famous double helix. Each strand contains millions of chemical building blocks called bases.
The HGP has opened the door to a wide range of genetic tests.
The project was started in 1990 by a group of international researchers, the United States’ National Institutes of Health (NIH) and the Department of Energy.
The goal was to sequence 3 billion letters, or base pairs, in the human genome, that make up the complete set of DNA in the human body.
By doing this, the scientists hoped to provide researchers with powerful tools, not only to understand the genetic factors in human disease, but also to open the door for new strategies for diagnosis, treatment, and prevention.