Name: how scientists edit dna for new traits
Uploaded: 2026-08-26T08:20:40.055Z
Duration: 1 min 34 s
Channel: JoVE

Genetic engineering is the modification of an organism&#x2019;s DNA.This process involves modifying the nucleotide sequence of a gene using genome editing techniques, such as CRISPR-Cas9.CRISPR uses a guide RNA to find a specific DNA region.Then, the Cas9 enzyme cuts the DNA at the specific sequence targeted by the guide RNA. This allows scientists to alter the DNA sequence in different ways.One type of genetic change is gene knockout, or deletion, in which a targeted gene is disrupted or removed. This prevents the organism from producing a functional protein.Alternatively, scientists can insert a new gene from another organism into the DNA, allowing the organism to produce a new protein.For example, a gene from a spider can be inserted into a goat&#x2019;s DNA, creating a transgenic goat that produces spider silk protein in its milk, which can be purified for biomedical and industrial applications.Similarly, in gene therapy, a functional gene can be introduced into a patient&#x2019;s cells to replace a defective gene. This enables the cells to produce a functional protein, which may help treat a genetic disease.

what is genetic engineering?

What is Genetic Engineering?

Genetic engineering is the process of modifying an organism&#x2019;s DNA to introduce new, desirable traits. Many organisms, from bacteria to plants and animals, have been genetically modified for academic, medical, agricultural, and industrial purposes. While genetic engineering has definite benefits, ethical concerns surround modifying humans and our food supply.<h4>Scientists can Deliberately Modify an Organism&#x2019;s Genome</h4>Genetic engineering is possible because the genetic code&#x2014;the way information is encoded by DNA&#x2014;and the structure of DNA are universal among all life forms. As a result, an organism&#x2019;s genetic code may be modified in several ways.The nucleotide sequence may be selectively edited by using techniques such as the CRISPR/Cas9 system. Known as the &#x22;molecular scissors,&#x22; the CRISPR/Cas9 system is an innate, prokaryotic immune response that has been co-opted for editing genetic information.A gene may also be removed from an organism to create a &#x201C;knockout,&#x201D; or introduced to create a &#x201C;knockin,&#x201D; through a process called gene targeting. This method relies on homologous recombination&#x2014;genetic exchange between DNA molecules that share an extended region with similar sequences&#x2014;to modify an endogenous gene.Scientists can also insert a gene from one organism into the genome of another, resulting in a transgenic organism. Generally, DNA combined from different sources is called recombinant DNA. The organism that receives that DNA is considered a genetically modified organism or GMO.<h4>Genetic Engineering Impacts Human Health and Well-Being</h4>Genome editing has significantly impacted scientific research, agriculture, industry, and medicine. Molecular biology research often inserts transgenes&#x2014;foreign genes&#x2014;into bacteria and viruses to study gene function and expression. Bacteria were the first organisms to be genetically engineered. Scientists introduced the human insulin gene to produce synthetic insulin that is used by people with diabetes.A technique called gene therapy allows a new gene to be inserted into a person so that the protein it encodes can be expressed within their cells. Gene therapy provides a cure or treatment for some serious and otherwise untreatable genetic diseases. Scientists modified viruses to deliver new genes to host cells. These customized viruses can infect diseased cells and insert a correct copy of a defective gene, treating human disorders such as Severe Combined Immunodeficiency (SCID).Although many gene therapy treatments use modified viruses, the CRISPR/Cas9 system has become an increasingly popular technique. The CRISPR/Cas9 system cuts DNA by using a guide&#x2014;RNA sequences known as CRISPR&#x2014;to direct the &#x201C;molecular scissors&#x201D;&#x2014;an enzyme called Cas9&#x2014;to specific sites in the genome. Scientists use this molecular tool to add, remove, or alter genetic material. CRISPR/Cas9 has been used in mouse models to correct errors in genes that are responsible for Duchenne muscular dystrophy, Hepatitis B, cataracts, and cardiovascular disease.While genetic engineering can yield new treatments for diseases, it can also be used for other practical purposes. Transgenic goats have been developed that produce spider silk in their milk for industrial use. In agriculture, some plants have been genetically modified to improve characteristics such as nutritional content and pest resistance. Recent and future advances in genetic engineering will likely continue to impact both human health and well-being.<h4>Ethical Concerns Regarding Genetic Engineering</h4>Genetic engineering has great potential, but where do we draw the line? Scientists and society must answer this question. Human genome editing, especially in germline cells, is a major ethical concern. Most gene therapies modify somatic cells, so genetic changes only affect the individual. Changes to a person&#x2019;s germline, however, are also inherited by their offspring.In 2018, a scientist shocked the world when he allegedly created the first babies genetically modified with CRISPR. He attempted to make the twin baby girls resistant to HIV by introducing an unstudied germline mutation. His actions sparked outrage and concern as scientists and the public grappled with what this meant for humankind. It remains unclear how this will affect the girls&#x2019; health, their future offspring, or the population.Another concern is the use of foreign genetic material to improve the food supply. Plants are the most common genetically modified food source, with 28 countries growing nearly 450 million acres of GM crops globally. While there is enormous potential to secure food supply for a growing world population, scientifically sound, long-term studies are needed to address the concerns of GMO critics.

Overview

Genetic engineering is the process of modifying an organism&#x2019;s DNA to introduce new, desirable traits. Many organisms, from bacteria to ...

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how scientists edit dna for new traits

Genetic engineering changes an organism’s DNA to add useful traits. Scientists use it in bacteria, plants, animals, and even viruses for research, medicine, agriculture, and industry. It can bring major benefits, but it also raises ethical concerns about humans and the food supply.

This work is possible because DNA has the same basic structure and genetic code across life. That shared code lets scientists modify DNA in several ways. One method is CRISPR/Cas9, often called molecular scissors, which uses CRISPR guide RNA and the Cas9 enzyme to cut DNA at specific sites. Scientists can also remove a gene to make a knockout, add a gene to make a knockin, or use gene targeting and homologous recombination, which is the exchange of DNA between similar sequences, to change an existing gene.

Scientists can also move a gene from one organism into another. The result is a transgenic organism, and DNA from different sources is called recombinant DNA. When an organism receives that DNA, it is considered a genetically modified organism, or GMO.

Genome editing has had a major effect on research, medicine, farming, and industry. In molecular biology, scientists often insert transgenes, or foreign genes, into bacteria and viruses to study how genes work. Bacteria were the first organisms to be genetically engineered. Scientists also added the human insulin gene to make synthetic insulin for people with diabetes.

Genetic engineering is also used in gene therapy. In this approach, a new gene is inserted into a person so cells can make the protein it encodes. Some treatments use modified viruses to carry the new gene into host cells. These viruses can infect diseased cells and add a correct copy of a faulty gene, which has helped treat disorders such as Severe Combined Immunodeficiency, or SCID.

CRISPR/Cas9 has become an increasingly popular tool for this kind of work. It uses a guide RNA to direct Cas9 to a chosen spot in the genome. Scientists can use it to add, remove, or change genetic material. In mouse models, CRISPR/Cas9 has been used to correct gene errors linked to Duchenne muscular dystrophy, Hepatitis B, cataracts, and cardiovascular disease.

Genetic engineering is not limited to health care. Transgenic goats have been made to produce spider silk in their milk for industrial use. In agriculture, some plants have been modified to improve nutritional content and pest resistance. These examples show how genome editing can affect both human health and everyday products.

There are also serious ethical questions. Germline editing is especially controversial because changes in germline cells can be passed to offspring, while somatic cell changes affect only the individual. In 2018, a scientist shocked the world when he allegedly created the first CRISPR-modified babies and tried to make twin girls resistant to HIV with an untested germline mutation. The long-term effects on the children, their future offspring, and the population remain unclear.

Food is another major concern. Plants are the most common genetically modified food source, and many countries grow GM crops on large areas of farmland. Genetic engineering may help support a growing population, but long-term, scientifically sound studies are still needed to address concerns from GMO critics.

How Scientists Edit DNA for New Traits

Genetic engineering changes an organism’s DNA to add useful traits. Scientists use it in bacteria, plants, animals, and even viruses for research, medicine, agriculture, and industry. It can bring major benefits, but it also raises ethical concerns about humans and the food supply. This work is possible because DNA has the same basic structure and genetic code across life. That shared code lets scientists modify DNA in several ways. One method is CRISPR/Cas9, often called molecular scissors,...

dna isolation

Steps in DNA Extraction

DNA extraction is the process of removing and purifying DNA from cells. It is used in many biotechnology and research applications, including molecular cloning. The main goal is to free DNA from the cell and prepare it for later study or use. The first step is cell lysis, which means breaking cells open. Researchers may use a homogenizer, sonicator, or bead beater to physically lyse the cells. They also often add detergent to chemically disrupt the lipid-based cell membranes. This helps...

recombinant dna technology

Recombinant DNA in Cloning and GMOs

Recombinant DNA is made by joining DNA from different sources in the lab. Scientists often use it to clone genes and study them in cells that are easy to handle, such as bacteria. Organisms that carry recombinant DNA are called genetically modified organisms, or GMOs. This technology gives scientists new tools for research, medicine, and agriculture. To build recombinant DNA, researchers place a gene of interest into a vector, which is a DNA carrier that moves foreign DNA into a host cell. The...

PCR Cycle for DNA Amplification

PCR is a laboratory method for making many copies of a DNA segment. It can turn a small amount of DNA into millions or even billions of copies in just a few hours. The process uses a heat-resistant DNA polymerase inside a machine called a thermocycler. PCR was developed by Kary Mullis in 1983, and he received the 1993 Nobel Prize in Chemistry for it. The method is fast, relatively inexpensive, and precise. It has become useful for molecular cloning, gene mutagenesis, pathogen detection, gene...

complementary dna

From mRNA to cDNA for Gene Studies

Complementary DNA, or cDNA, is made from messenger RNA (mRNA) so scientists can study which genes are active in cells and tissues. Only genes that are transcribed into mRNA are expressed. By extracting mRNA from cells, researchers can compare gene expression across samples. cDNA is produced by reverse transcription. This process copies mRNA into DNA, which is useful because mRNA does not contain introns, or non-coding regions, and other regulatory sequences. As a result, cDNA can help...

antibiotic selection

Antibiotic Resistance in Cloning

Antibiotic resistance genes help scientists find bacteria that took up a plasmid with a gene of interest. In genetic engineering, this resistance is used as a marker, not just as a medical concern. The same process also connects to the growing problem of resistant bacteria in the real world. Antibiotics, such as penicillin, stop bacterial growth or kill bacteria. When bacteria naturally have, or are engineered to carry, an antibiotic resistance gene, the antibiotic no longer works on them.

transgenic organisms

Creating Transgenic Plants and Animals

Transgenic organisms are genetically engineered to carry a transgene, which is a gene from a different species, in their genome. The inserted gene may be a new gene for that organism or a different version of one it already has. Scientists usually make transgenes with recombinant DNA and DNA cloning methods. Researchers use transgenic bacteria, plants, and animals to answer biological questions and to build useful tools. To make a transgenic organism, they first choose a transgenesis method,...

in-vitro mutagenesis (gene knockouts)

Knockout Mice and Gene Replacement

Knockout mice help researchers study gene function by showing what happens when a gene is turned off. These engineered animals are also useful for modeling human diseases such as cancer, Parkinson’s disease, and diabetes. A specific gene can be targeted by using a targeting vector, which is a piece of engineered DNA that replaces the normal gene and inactivates it. The vector has matching DNA sequences on both ends. These homologous sequences let the vector swap in for the target gene through...

crispr

CRISPR-Cas9 Gene Editing in Action

CRISPR-Cas9 is a genome editing tool that lets scientists change DNA at a specific location. It can add, remove, or rearrange genetic material. Researchers study it because it may help treat genetic disorders such as hemophilia and sickle cell anemia. CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats, and Cas9 is a CRISPR-associated protein 9. The basic system includes a Cas9 endonuclease, which is an enzyme that cuts DNA, and a small RNA that guides Cas9 to the...

gene therapy

Gene Delivery for Serious Diseases

Gene therapy is a technique used to treat serious disease by adding a gene to a person’s cells. The added gene may be a healthy copy of a mutated gene. It may also be a different gene that inactivates or compensates for the disease-causing gene. One example is severe combined immunodeficiency, or SCID, caused by a mutation in the gene for adenosine deaminase. In that case, a working copy of the gene can be inserted so the patient’s cells make the enzyme again. This can cure the disease in some...

embryonic stem cells

How Embryonic Stem Cells Become Specialized

Embryonic stem cells are pluripotent cells that have not yet specialized. Pluripotent means they can give rise to many different cell types in the body. Because of this, they are useful in science and medicine for making cells needed in research or for replacing cells lost to damage or disease. These cells come from the inner cell mass of a blastocyst, which is an early embryo about 3 to 5 days after fertilization in humans. At this stage, the embryo has not yet implanted in the uterus. Human...

adult stem cells

Adult Stem Cells in the Small Intestine

Adult stem cells help maintain tissues by replacing old or damaged cells. These undifferentiated cells divide to make more stem cells or progenitor cells, which then become mature, specialized cells. Small groups of adult stem cells are found in many tissues, including the bone marrow, brain, skin, and gut. The small intestine shows this process clearly. Its lining, called the epithelium, is renewed continuously by adult stem cells. It is also the fastest replaced tissue in the human body,...

induced pluripotent stem cells

Reprogramming Mature Cells into Stem Cells

Reprogramming mature cells into stem cells lets scientists turn specialized cells back into an unspecialized state. These cells are called induced pluripotent stem cells, or iPSCs. Like embryonic stem cells, iPSCs are pluripotent, which means they can form all cell types. To make iPSCs, researchers start with mature cells such as skin fibroblasts or blood cells. The cells are grown in culture, and genes for several transcription factors are delivered with a viral vector. The cells then make...

reproductive cloning

Cloning Animals with SCNT

Reproductive cloning can produce a genetically identical copy of an entire organism. In adult animals, this is usually done with somatic cell nuclear transfer, or SCNT. Another way clones can form is by splitting an early embryo, which is similar to how identical twins arise naturally. In SCNT, an egg cell is taken from an animal and its nucleus is removed. This creates an enucleated egg. A somatic cell, which is any body cell that is not a sex cell, is then taken from the animal to be cloned.

genomics

Genomics and DNA Sequencing

Genomics studies the full set of genetic material in an organism. In humans, that genome includes the DNA carried in 23 pairs of chromosomes in the nucleus, along with mitochondrial DNA. Genomics looks at both coding DNA and non-coding DNA, which helps scientists study how living things are built and how they differ. This field is useful in many areas of biology and medicine. Scientists use genomics to build phylogenetic trees, improve crop productivity and sustainability, help with criminal...

key terms and concepts

Explore how scientists edit DNA using CRISPR, gene targeting, and transgenic methods. Learn real examples in medicine, farming, and ethics.

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How Scientists Edit DNA for New Traits

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