In many ways, the mid to late 19th century was the birth of the study of genetics — the scientific study of heredity and genes.
The scientific endeavor to understand genes has also gained more attention among the public in recent years, due largely to the efforts of the Human Genome Project.
This worldwide collaborative project, started in the early 1990s, sought to identify and map the human genome. Their efforts are ongoing.
But, as research evolves and technologies continue to advance, another area of interest has emerged — gene editing.
What is gene editing exactly? What is it used for? Let’s take a closer look.
A Closer Look at Genes
Understanding the definitive role of genes is still ongoing. But, on the surface, we do know that genes play an important role in determining who we are and how we look.
In short, genes are the basic unit of physical inheritance — our physical traits. Genes carry information that determine what you look like (e.g. eye color, height, etc.)
These traits are passed onto offspring — or inherited — from parents. For example, if both parents have blue eyes (or carry the blue-eyed gene) there is a good chance you will too. Genes also play a key role in determining where your ancestors might have come from.
Though research is ongoing, scientists believe that the human body contains around 20,000 genes.
Chromosomes, DNA, and Genes
Genes are arranged on cellular structures known as chromosomes. These thread-like structures are located within the nucleus of the cell. Structurally, chromosomes are composed of centromeres, which separate its long and short arms, and telomeres.
Telomeres have a protective role and are located at the tail ends of the chromosomes. These shorten every time cellular division occurs.
Chromosomes are made of both proteins and deoxyribonucleic acid (DNA), which houses genetic information.
DNA is made up of nucleotides — the building blocks. These molecules form the two, long-spiraling strands of the famous double-helix structure of the DNA, which are paired together via nitrogen bases.
What makes matters complicated is the fact that only a portion of this single DNA molecule corresponds to a single gene. The human genome, or set of genes, contains a staggering 3 billion of these base pairs.
What Is Gene Editing?
Every living organism carries genes, this includes humans, plants, animals, and even bacteria.
Gene editing, also called genome editing or engineering, is a method that allows scientists to change, alter, or modify DNA in some living organisms.
The first gene-editing technologies emerged in the 1980s and 90s, largely due to the discovery of zinc finger nuclease (ZFN), the first technique that allowed highly targeted genome engineering.
How Gene Editing Works
In short, with the use of genome editing technologies, scientists can make specific changes to the DNA of a cell or organism. It involves making cuts at certain parts of the DNA sequence using enzymes called engineered nucleases.
In effect, these enzymes are used to create a break in the double-stranded DNA at a specific point in the desired gene. They act as molecular scissors making a “cut” in the DNA sequence. This allows scientists to add, remove, replace the DNA where it was cut.
Today, a powerful tool known as CRISPR (Clustered regularly interspaced short palindromic repeats) is the most advanced and widely used gene-editing tool. CRISPR is seen as the most effective and accurate tool for gene editing by most scientists today.
What Is Gene Editing Used for?
In theory, gene editing could be used to edit the genome of any organism. For example, it has been used in biotechnology to modify crops to help improve yields.
For humans, gene editing uses fall into two main categories: Research and disease treatment.
Gene Editing for Research
Gene editing is most widely used in the area of scientific research. Since it allows DNA to be changed in cells and organisms, researchers can better understand the biology of certain organisms and how they work.
This also has positive implications for research on diseases. For example, gene editing is being used to create knockout models of certain health conditions in various animals. This allows researchers to study the link between disease and genetics.
Gene Editing for Disease Treatment
Understanding how the human genome works helps give rise to potential treatments for disease. Gene editing has opened the door for a treatment technique known as gene therapy.
This experimental technique seeks to treat certain diseases by altering a person’s genetic material. In effect, this technique works by introducing healthy copies of defective genes in a person’s cells.
There are currently two categories of gene therapy: Germline therapy (makes changes to DNA in reproductive cells) and somatic therapy (makes changes in non-reproductive cells).
Ethical Concerns Surrounding Gene Editing
Gene editing is not without controversy. The crux of the ethical dilemma lies in the use of gene editing for reproductive purposes and the moral and religious objections to the use of human embryos for research.
Currently, the U.S. and National Institute of Health does not fund any use of gene editing in human embryos.
The study of genetics evolves more and more every year as research and technologies continue to advance. But one truth remains: Genes are complicated.
We inherit our genes from our parents, these are responsible for our physical traits. But, genes can also be the link to other physical factors concerning our health.
Gene editing allows scientists to add, remove, or modify DNA in living organisms.
It has made big waves in the area of gene research and continues to have positive impacts in the area of disease treatment.