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

Gentechnik ist die Ver&#xE4;nderung des genetischen Codes, der DNA eines Organismus.
 Die Nukleotidsequenz eines Gens kann unter Verwendung von Genomeditiertechniken wie CRISPR / Cas9 ge&#xE4;ndert werden.
 Ein Gen k&#xF6;nnte entfernt oder ganz ausgeschaltet werden, oder ein neues k&#xF6;nnte eingef&#xFC;gt werden, indem beispielsweise ein Gen einer anderen Spezies hinzugef&#xFC;gt wird, um einen transgenen Organismus zu erzeugen.
 Infolgedessen k&#xF6;nnen Forscher und Kliniker die von einem Organismus produzierten Proteine ver&#xE4;ndern.
 Zum Beispiel kann in der Gentherapie ein Gen in einen Patienten eingef&#xFC;hrt werden, um ein Protein zu produzieren, dass ihm fehlt, was m&#xF6;glicherweise seine Krankheit heilt.

Georges, Fawzy und Heather Ray. "Genome Editing of Crops: A Renewed Opportunity for Food Security." GM Crops & Food 8, Nr. 1 (2. Januar 2017): 1–12. [<a href="https://doi.org/10.1080/21645698.2016.1270489" target="__blank">Quelltext</a>]

Thurtle-Schmidt, Deborah M. und Te-Wen Lo. 2018. "Molekularbiologie am Puls der Zeit: Ein Überblick über die CRISPR/CAS9-Genbearbeitung für Studenten." Biochemie und molekularbiologische Ausbildung 46 (2): 195–205. [<a href="https://doi.org/10.1002/bmb.21108" target="__blank">Quelle</a>]

was ist gentechnik?

What is Genetic Engineering?

<h4>&#xDC;berblick</h4>
 
 Die Gentechnik ist der Prozess der Ver&#xE4;nderung der DNA eines Organismus, um neue, w&#xFC;nschenswerte Eigenschaften einzuf&#xFC;hren. Organismen von Bakterien bis hin zu Pflanzen und Tieren, wurden bereits f&#xFC;r akademische, medizinische, landwirtschaftliche und industrielle Zwecke genetisch modifiziert. W&#xE4;hrend die Gentechnik eindeutige Vorteile hat, gibt es gleichzeitig ethische Bedenken bez&#xFC;glich der genetischen Ver&#xE4;nderung des Menschen und unserer Lebensmittelversorgung.
 
 <h4>Wissenschaftler k&#xF6;nnen gezielt das Genom eines Organismus ver&#xE4;ndern</h4>
 
 Die Gentechnik ist durchf&#xFC;hrbar, da der genetische Code, das hei&#xDF;t die Art wie die DNA Informationen speichert und ihre Struktur, allgemeing&#xFC;ltig ist in allen Lebensformen. Daher kann der genetische Code eines Organismus auf mehrere Arten ver&#xE4;ndert werden.
 
 Eine Nukleotidsequenz kann mit Techniken wie dem CRISPR/Cas9-System spezifisch ver&#xE4;ndert werden. Bekannt als die &#x22;molekulare Schere&#x22; ist das CRISPR/Cas9-System eine angeborene, prokaryotische Immunantwort, die zur Ver&#xE4;nderung der genetischen Information ausgew&#xE4;hlt wurde.
 
 Ein Gen kann auch aus einem Organismus entfernt werden, wobei ein &#x201C;Knockout&#x201D; geschaffen wird oder eingef&#xFC;hrt werden, wobei ein &#x201C;Knockin&#x201D; entsteht. Diesen Prozess bezeichnet man allgemein als gezielte Genmodifikation oder Gene-Targeting. Diese Methode beruht auf der homologen Rekombination um ein endogenes Gen zu modifizieren. Dabei findet ein genetischer Austausch zwischen DNA-Molek&#xFC;len, die eine weite Region an &#xE4;hnlichen Sequenzen teilen.
 
 Wissenschaftler k&#xF6;nnen auch ein Gen von einem Organismus in das Genom eines anderen Organismus einf&#xFC;hren, wobei ein transgener Organismus entsteht. Im Allgemeinen wird die aus verschiedenen Quellen vereinte DNA als rekombinante DNA bezeichnet. Der Organismus, der diese DNA erh&#xE4;lt, gilt als gentechnisch ver&#xE4;nderter Organismus oder GVO.
 
 <h4>Gentechnik beeinflusst die menschliche Gesundheit und das Wohlbefinden</h4>
 
 Die Ver&#xE4;nderung von Genomen hat die wissenschaftliche Forschung, Landwirtschaft, Industrie und Medizin ma&#xDF;geblich beeinflusst. In der molekularbiologischen Forschung werden oft Fremdgene (Transgene) in Bakterien und Viren eingef&#xFC;hrt, um die Funktion und Expression von Genen zu untersuchen. Bakterien waren die ersten Organismen, die gentechnisch ver&#xE4;ndert wurden. Wissenschaftler f&#xFC;hrten das menschliche Insulin-Gen in Bakterien ein, um synthetisches Insulin zu produzieren, dass von Menschen mit Diabetes benutzt wird.
 
 Die Gentherapie ist eine Technik, die es erlaubt ein neues Gen in eine Person einzuf&#xFC;hren. So kann das Protein, f&#xFC;r das es kodiert, in den Zellen exprimiert werden. Die Gentherapie bietet eine Heilung oder Behandlung f&#xFC;r einige schwere und sonst nicht behandelbare genetische Krankheiten. Daf&#xFC;r ver&#xE4;nderten Wissenschaftler Viren, um neue Gene in die Wirtszellen zu bringen. Diese ver&#xE4;nderten Viren k&#xF6;nnen in erkrankte Zellen eindringen und eine funktionst&#xFC;chtige Kopie des defekten Gens einbauen und so menschliche Erkrankungen wie die Schweren Kombinierten Immundefekte (SCID) behandeln.
 
 Obwohl viele gentherapeutische Therapien mit ver&#xE4;nderten Viren durchgef&#xFC;hrt werden, ist das CRISPR/Cas9-System zu einer immer beliebteren Technik geworden. Das CRISPR/Cas9-System schneidet DNA mit Hilfe einer leader-RNA Sequenz, die CRISPR genannt wird. Diese Sequenz f&#xFC;hrt die &#x201C;molekulare Schere&#x201D;, ein Enzym namens Cas9, zu spezifische Stellen im Genom. Wissenschaftler verwenden dieses molekulare Werkzeug, um genetisches Material hinzuzuf&#xFC;gen, zu entfernen oder zu ver&#xE4;ndern. Das CRISPR/Cas9-Sytem wurde in Maus-Experimenten verwendet, um Genfehler in Krankheiten wie Duchenne-Muskeldystrophie, Hepatitis B, Grauer Star und Herz-Kreislauf-Erkrankungen zu beheben.
 
 Die Gentechnik kann neue Behandlungsmethoden f&#xFC;r Krankheiten hervorbringen, und gleichzeitig f&#xFC;r andere praktische Zwecke eingesetzt werden. Zum Beispiel wurden transgene Ziegen entwickelt, die in ihrer Milch Spinnenseide f&#xFC;r die industrielle Nutzung produzieren. In der Landwirtschaft wurden einige Pflanzen gentechnisch ver&#xE4;ndert, um Eigenschaften wie N&#xE4;hrstoffgehalt und Sch&#xE4;dlingsresistenz zu verbessern. J&#xFC;ngste und zuk&#xFC;nftige Fortschritte in der Gentechnik werden wahrscheinlich weiterhin 
 zu der Gesundheit und des Wohlbefindens des Menschen beitragen.
 
 <h4>Ethische Bedenken in der Gentechnik</h4>
 
 Die Gentechnik hat gro&#xDF;es Potenzial. Aber wo ziehen wir die Grenze? Diese Frage m&#xFC;ssen die Wissenschaftler und die Gesellschaft beantworten. Die Ver&#xE4;nderung des menschlichen Genoms, insbesondere der Keimzellen, ist ein gro&#xDF;es ethisches Problem. Die meisten Gentherapien modifizieren somatische Zellen, so dass die genetischen Ver&#xE4;nderungen nur das Individuum betreffen. Jedoch werden Ver&#xE4;nderungen in den Keimzellen eines Menschen auch an die Nachkommen vererbt.
 
 Im Jahr 2018 schockierte ein Wissenschaftler die Welt, als er angeblich die ersten durch CRISPR genetisch ver&#xE4;nderten Babys schuf. Er versuchte, Zwillingsm&#xE4;dchen durch die Einf&#xFC;hrung einer wenig erforschten Keimbahnmutation immun gegen HIV zu machen. Seine T&#xE4;tigkeiten l&#xF6;sten Emp&#xF6;rung und Besorgnis aus, w&#xE4;hrend sich die Wissenschaftler und die &#xD6;ffentlichkeit mit der Frage besch&#xE4;ftigten, was dies f&#xFC;r die Menschheit bedeutet. Es bleibt unklar, wie sich das auf die Gesundheit der M&#xE4;dchen, ihre zuk&#xFC;nftigen Nachkommen oder die Bev&#xF6;lkerung auswirkt. 
 
 Ein weiteres Besorgnis verursacht die Nutzung von fremdem genetischem Material zur Verbesserung der Nahrungsmittelversorgung. Pflanzen sind die h&#xE4;ufigste genetisch ver&#xE4;nderte Nahrungsquelle, wobei weltweit 28 L&#xE4;nder fast 450 Millionen Hektar genetisch ver&#xE4;nderte Pflanzen anbauen. W&#xE4;hrend es ein enormes Potenzial f&#xFC;r die Sicherung der Nahrungsmittelversorgung f&#xFC;r die wachsende Weltbev&#xF6;lkerung bietet, sind wissenschaftlich belegte, langfristige Studien erforderlich, um den Bedenken der GVO-Kritiker zu begegnen.

Was ist Gentechnik?

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

what is genetic engineering?

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.

How Scientists Edit DNA for New Traits | JoVE K12

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How Scientists Edit DNA for New Traits

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