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

Engenharia gen&#xE9;tica &#xE9; a modifica&#xE7;&#xE3;o do c&#xF3;digo gen&#xE9;tico, o DNA, de um organismo. A sequ&#xEA;ncia de nucleot&#xED;deos de um gene pode ser alterada usando t&#xE9;cnicas de edi&#xE7;&#xE3;o de genoma, como CRISPR Cas9. Um gene pode ser removido ou completamente nocauteado, ou um novo pode ser inserido.Por exemplo, adicionar um gene de outra esp&#xE9;cie para criar um organismo transg&#xEA;nico. Como resultado, pesquisadores e m&#xE9;dicos podem alterar as prote&#xED;nas produzidas por um organismo. Por exemplo, na terapia gen&#xE9;tica, um gene pode ser introduzido em um paciente para produzir uma prote&#xED;na que lhes falta, potencialmente curando sua doen&#xE7;a.

Georges, Fawzy e Heather Ray. "Edição do genoma das culturas: uma oportunidade renovada para a segurança alimentar." GM Crops & Food 8, nº 1 (2 de janeiro de 2017): 1–12. [<a href="https://doi.org/10.1080/21645698.2016.1270489" target="__blank">Fonte</a>]

Thurtle-Schmidt, Deborah M. e Te-Wen Lo. 2018. "Biologia Molecular na Vanguarda: Uma Revisão sobre a Edição de Genes CRISPR/CAS9 para Alunos de Graduação." Educação em Bioquímica e Biologia Molecular 46 (2): 195–205. [<a href="https://doi.org/10.1002/bmb.21108" target="__blank">Fonte</a>]

o que é a engenharia genética?

What is Genetic Engineering?

<h4>Vis&#xE3;o Geral</h4>
 
 A engenharia gen&#xE9;tica &#xE9; o processo de modifica&#xE7;&#xE3;o do DNA de um organismo para introduzir novas caracter&#xED;sticas desej&#xE1;veis. Muitos organismos, desde bact&#xE9;rias a plantas e animais, t&#xEA;m sido geneticamente modificados para fins acad&#xE9;micos, m&#xE9;dicos, agr&#xED;colas e industriais. Embora a engenharia gen&#xE9;tica tenha claros benef&#xED;cios, preocupa&#xE7;&#xF5;es &#xE9;ticas envolvem a modifica&#xE7;&#xE3;o de humanos e dos nossos suplementos alimentares.
 
 <h4>Os Cientistas Podem Modificar Deliberadamente o Genoma de um Organismo</h4>
 
 A engenharia gen&#xE9;tica &#xE9; poss&#xED;vel porque o c&#xF3;digo gen&#xE9;tico&#x2014;a forma como a informa&#xE7;&#xE3;o &#xE9; codificada pelo DNA&#x2014;e a estrutura do DNA s&#xE3;o universais entre todas as formas de vida. Como resultado, o c&#xF3;digo gen&#xE9;tico de um organismo pode ser modificado de v&#xE1;rias maneiras.
 
 A sequ&#xEA;ncia de nucle&#xF3;tidos pode ser editada seletivamente usando t&#xE9;cnicas como o sistema CRISPR/Cas9. Conhecido como &#x22;tesoura molecular&#x22;, o sistema CRISPR/Cas9 &#xE9; uma resposta imune inata e procari&#xF3;tica que foi cooptada para editar informa&#xE7;&#xF5;es gen&#xE9;ticas.
 
 Um gene tamb&#xE9;m pode ser removido de um organismo para criar um &#x201C;knockout&#x201D;, ou introduzido para criar um &#x201C;knockin&#x201D;, atrav&#xE9;s de um processo chamado gene targeting. Este m&#xE9;todo baseia-se na recombina&#xE7;&#xE3;o hom&#xF3;loga&#x2014;troca gen&#xE9;tica entre mol&#xE9;culas de DNA que compartilham uma extensa regi&#xE3;o com sequ&#xEA;ncias semelhantes&#x2014;para modificar um gene end&#xF3;geno.
 
 Os cientistas tamb&#xE9;m podem inserir um gene de um organismo no genoma de outro, resultando em um organismo transg&#xE9;nico. Geralmente, o DNA combinado de diferentes fontes &#xE9; chamado DNA recombinante. O organismo que recebe esse DNA &#xE9; considerado um organismo geneticamente modificado ou OGM.
 
 <h4>A Engenharia Gen&#xE9;tica Impacta a Sa&#xFA;de e Bem-estar Humanos</h4>
 
 A edi&#xE7;&#xE3;o de genomas teve um impacto significativo na investiga&#xE7;&#xE3;o cient&#xED;fica, agricultura, ind&#xFA;stria e medicina. A investiga&#xE7;&#xE3;o em biologia molecular insere frequentemente transgenes&#x2014;genes estranhos&#x2014;em bact&#xE9;rias e v&#xED;rus para estudar a fun&#xE7;&#xE3;o e a express&#xE3;o gen&#xE9;tica. As bact&#xE9;rias foram os primeiros organismos a serem geneticamente modificados. Os cientistas introduziram o gene da insulina humana para produzir insulina sint&#xE9;tica que &#xE9; usada por pessoas com diabetes.
 
 Uma t&#xE9;cnica chamada terapia gen&#xE9;tica permite que um novo gene seja inserido em uma pessoa para que a prote&#xED;na que codifica possa ser expressa dentro das suas c&#xE9;lulas. A terapia gen&#xE9;tica fornece uma cura ou tratamento para algumas doen&#xE7;as gen&#xE9;ticas graves e intrat&#xE1;veis. Os cientistas modificaram v&#xED;rus para entregar novos genes &#xE0;s c&#xE9;lulas hospedeiras. Esses v&#xED;rus personalizados podem infectar c&#xE9;lulas doentes e inserir uma c&#xF3;pia correta de um gene defeituoso, tratando dist&#xFA;rbios humanos como a Imunodefici&#xEA;ncia Combinada Grave (SCID).
 
 Embora muitos tratamentos de terapia gen&#xE9;tica usem v&#xED;rus modificados, o sistema CRISPR/Cas9 tornou-se uma t&#xE9;cnica cada vez mais popular. O sistema CRISPR/Cas9 corta o DNA usando um guia&#x2014;sequ&#xEA;ncias de RNA conhecidas como CRISPR&#x2014;para guiar a &#x201C;tesoura molecular&#x201D;, uma enzima chamada Cas9, para locais espec&#xED;ficos do genoma. Os cientistas usam esta ferramenta molecular para adicionar, remover ou alterar material gen&#xE9;tico. O CRISPR/Cas9 tem sido usado em modelos de murganhos para corrigir erros em genes respons&#xE1;veis pela distrofia muscular de Duchenne, Hepatite B, cataratas e doen&#xE7;as cardiovasculares.
 
 Embora a engenharia gen&#xE9;tica possa produzir novos tratamentos para doen&#xE7;as, ela tamb&#xE9;m pode ser usada para outros fins pr&#xE1;ticos. Foram desenvolvidas cabras transg&#xE9;nicas que produzem seda de aranha no seu leite para uso industrial. Na agricultura, algumas plantas foram geneticamente modificadas para melhorar caracter&#xED;sticas como o conte&#xFA;do nutricional e a resist&#xEA;ncia a pragas. Os avan&#xE7;os recentes e futuros na engenharia gen&#xE9;tica provavelmente continuar&#xE3;o a ter impacto tanto na sa&#xFA;de como no bem-estar humanos.
 
 <h4>Preocupa&#xE7;&#xF5;es &#xC9;ticas em Rela&#xE7;&#xE3;o &#xE0; Engenharia Gen&#xE9;tica</h4>
 
 A engenharia gen&#xE9;tica tem grande potencial, mas onde colocamos o limite? Os cientistas e a sociedade devem responder a essa pergunta. A edi&#xE7;&#xE3;o de genomas humanos, especialmente em c&#xE9;lulas germinativas, &#xE9; uma grande preocupa&#xE7;&#xE3;o &#xE9;tica. A maioria das terapias gen&#xE9;ticas modificam c&#xE9;lulas som&#xE1;ticas, ent&#xE3;o as altera&#xE7;&#xF5;es gen&#xE9;ticas s&#xF3; afetam o indiv&#xED;duo. Mudan&#xE7;as na linha germinativa de uma pessoa, no entanto, tamb&#xE9;m s&#xE3;o herdadas pelos seus filhos.
 
 Em 2018, um cientista chocou o mundo quando alegadamente criou os primeiros beb&#xE9;s geneticamente modificados com CRISPR. Ele tentou tornar as meninas g&#xE9;meas resistentes ao HIV introduzindo uma muta&#xE7;&#xE3;o germinativa n&#xE3;o estudada. As suas a&#xE7;&#xF5;es provocaram indigna&#xE7;&#xE3;o e preocupa&#xE7;&#xE3;o enquanto cientistas e o p&#xFA;blico lidavam com o que isso significava para a humanidade. Ainda n&#xE3;o est&#xE1; claro como isso ir&#xE1; afetar a sa&#xFA;de das meninas, os seus futuros filhos ou a popula&#xE7;&#xE3;o.
 
 Outra preocupa&#xE7;&#xE3;o &#xE9; o uso de material gen&#xE9;tico estranho para melhorar os suplementos alimentares. As plantas s&#xE3;o a fonte de alimento geneticamente modificada mais comum, com 28 pa&#xED;ses cultivando cerca de 450 milh&#xF5;es de hectares de culturas GM globalmente. Embora exista um enorme potencial para garantir o fornecimento de alimentos para uma popula&#xE7;&#xE3;o mundial crescente, estudos cientificamente s&#xF3;lidos e de longo prazo s&#xE3;o necess&#xE1;rios para resolver as preocupa&#xE7;&#xF5;es dos cr&#xED;ticos do OGM.

O que é a Engenharia Genética?

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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