Name: steps in dna extraction
Uploaded: 2026-08-26T08:20:38.799Z
Duration: 1 min 58 s
Channel: JoVE

- [Istruttore] L&#x27;estrazione
del DNA &#xE8; la rimozione

e purificazione del DNA dalle cellule.

Innanzitutto, le cellule
vengono lisate, aperte a pezzi,

di solito attraverso una
combinazione di interruzione fisica

e trattamento con prodotti
chimici come il detergente

che dissolve la cellula
e le membrane nucleari.

Il contenuto pu&#xF2; quindi
fluttuare liberamente

nella soluzione circostante.

Successivamente, il DNA
deve essere separato

dalle altre molecole presenti.

Solventi organici, come
fenolo e cloroformio, sono

comunemente usati per separare
gli acidi nucleici dalle

proteine in base alla
loro diversa solubilit&#xE0;.

Inoltre, enzimi proteinasi e RNasi

possono essere usati per
degradare proteine e RNA,

lasciando intatto il DNA.

Il sale viene solitamente
aggiunto al campione

che stabilizza i gruppi di
fosfato carichi negativamente

nella spina dorsale del DNA,

e dopo l&#x27;aggiunta di alcol ghiacciato,

precipita il DNA fuori dalla soluzione.

Il precipitato bianco viene raccolto

girandolo in una centrifuga

dove si deposita sul fondo del tubo.

Dopo averlo lavato e risospeso

in una soluzione tampone,

il DNA estratto pu&#xF2;
finalmente essere utilizzato

nella ricerca o nelle
applicazioni biotecnologiche.

isolamento del dna

DNA Isolation

Il DNA delle cellule &#xE8; necessario per molte applicazioni biotecnologiche e di ricerca, come la clonazione molecolare. Per rimuovere e purificare il DNA dalle cellule, i ricercatori utilizzano vari metodi di estrazione del DNA. Mentre le specifiche dei diversi protocolli possono variare, alcuni concetti generali sono alla base del processo di estrazione del DNA.

<h4>Il processo</h4>

In primo luogo, le cellule devono essere lisate -rotte, aperte - per rilasciare il DNA in soluzione. Le cellule possono essere fisicamente lisate utilizzando apparecchiature come un omogeneizzatore, un sonicatore, o battitore , in modo da macinare o altrimenti applicare una forza per rompere le cellule aperte. Spesso, sostanze come il detersivo vengono aggiunte durante la lisi per interrompere chimicamente le membrane cellulari a base di lipidi, aiutando a rilasciare il DNA dal nucleo e dalla cellula. La filatura in una centrifuga sedimenta i detriti cellulari sul fondo e il &#x22;lisato&#x22;, (omogenato) contenente materiali cellulari, viene raccolto per un&#x27;ulteriore elaborazione.

Il DNA deve quindi essere separato da altre molecole cellulari, come l&#x27;RNA e le proteine. Pertanto, enzimi come RNAsi e Proteinasi K vengono spesso aggiunti durante o dopo la lisi per degradare l&#x27;RNA e le proteine, rispettivamente. Inoltre, solventi organici come fenolo e cloroformio sono comunemente utilizzati per separare il DNA dalle proteine. Tipicamente, il campione viene vortexato con fenolo-cloroformio e quindi centrifugato per separare le fasi acquose e organiche nel tubo. La fase acquosa contenente il DNA nella parte superiore pu&#xF2; quindi essere convogliata, lasciando dietro di s&#xE9; la proteina nella fase organica.

I sali vengono spesso aggiunti durante l&#x27;estrazione del DNA per stabilizzare il DNA e aiutare a precipitarlo fuori soluzione. Un metodo standard di precipitazione del DNA consiste nell&#x27;aggiungere al campione l&#x27;alcol ghiacciato, come l&#x27;etanolo o l&#x27;isopropanolo. Questo fa s&#xEC; che il DNA formi un precipitato bianco e nuvoloso all&#x27;interno del liquido nel tubo.

Il campione viene quindi filato in una centrifuga, causando la raccolta del DNA sul fondo del tubo come un pellet. Il pellet viene lavato rimuovendo il liquido, lavandolo nell&#x27;alcool e ruotandolo di nuovo. Dopo il lavaggio finale, il pellet viene ri-sospeso in un buffer, creando una soluzione acquosa di DNA purificato che &#xE8; pronto per essere studiato o utilizzato nella biotecnologia.

Isolamento del DNA

DNA from cells is required for many biotechnology and research applications, such as molecular cloning. To remove and purify DNA from cells, researchers ...

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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 release DNA from the nucleus and the rest of the cell.

After lysis, the sample is spun in a centrifuge. This causes cell debris to settle at the bottom, while the liquid lysate is kept for the next steps. The DNA then has to be separated from other cellular molecules, such as RNA and proteins. Enzymes like RNase and Proteinase K are often added to break down RNA and proteins, and phenol-chloroform can be used to separate DNA from protein.

During the phenol-chloroform step, the sample is vortexed and centrifuged again. The tube separates into an aqueous phase and an organic phase. The DNA stays in the aqueous phase at the top, and this layer can be pipetted off. Salts are often added to help stabilize the DNA and support precipitation.

To collect the DNA, ice-cold alcohol such as ethanol or isopropanol is added. The DNA then forms a white, cloudy precipitate in the tube. Another centrifuge spin pulls this DNA into a pellet at the bottom. The pellet is washed with alcohol, spun again, and then re-suspended in buffer to make a purified DNA solution ready for biotechnology work.

Steps in DNA Extraction

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dna isolation

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...

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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

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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

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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...

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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

Learn the main steps in DNA extraction, including cell lysis, centrifugation, protein removal, and DNA precipitation for purified samples.

Steps in DNA Extraction | JoVE K12

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Steps in DNA Extraction

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