Clear Everything about Vector

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• Tell me what is a vector in genetic engineering?

In genetic engineering, a vector is a vehicle used to transfer foreign genetic material into a target organism. It can be a plasmid, virus, or other DNA molecule that carries the desired gene or genes. Vectors are important tools for introducing new traits into organisms, such as bacteria or plants, for various purposes including research, biotechnology, and medical applications.

• So, do we have to put DNA into another organism? Right?

Yes, that's correct. In genetic engineering, scientists often insert DNA, which contains specific genes or genetic instructions, into the genome of another organism. This process allows them to introduce new traits or characteristics into the organism, such as improved disease resistance, increased productivity, or the production of specific proteins.

• Besides DNA, can we add other things as a vector?

In genetic engineering, vectors primarily refer to DNA molecules used to carry and transfer genetic material into target organisms. However, depending on the context, other molecules or entities could serve similar functions. For example, in some biotechnological applications, nanoparticles or liposomes may be used to deliver genetic material into cells, effectively acting as vectors. Similarly, in gene therapy, viral vectors are commonly used to deliver therapeutic genes into human cells to treat genetic disorders. So while DNA molecules are the most common vectors, other materials can serve similar roles in certain applications.

• So, you have mentioned that we can transfer DNA into another organism, now is that DNA itself will work as a genetic material or that DNA will carry another genetic material? If DNA carries another genetic material, then what are those? 

When we talk about transferring DNA into another organism, typically the DNA being transferred contains specific genetic material or genes that encode for desired traits or proteins. This DNA serves as the genetic material that carries the instructions for those traits. In other words, the DNA itself is the genetic material that is being transferred. 

However, the DNA being transferred may also be part of a larger construct or vector that contains additional elements besides just the desired genes. These additional elements can include:

• Regulatory sequences: These are DNA sequences that control the expression of the inserted genes, determining when and where they are turned on or off within the organism.
• Selection markers: These are genes that confer resistance to specific antibiotics or other substances. They are included in the vector to help select organisms that have successfully taken up the vector DNA.
• Reporter genes: These are genes that produce easily detectable proteins or molecules, allowing researchers to monitor the expression of the inserted genes.

So, while the primary purpose of transferring DNA into another organism is to introduce specific genetic material, the DNA may also carry additional elements to facilitate its insertion and expression within the target organism.

• Ok got it, now tell me, what should be the characteristics a vector should have, so that we can recognise it? 

Certainly! Here are some key characteristics that help scientists recognize vectors:

• Selectable markers:
• Vectors often contain genes that confer resistance to certain antibiotics or other substances. This allows researchers to easily identify and select organisms that have taken up the vector.
• Origin of replication: 
• Vectors typically have a specific region where DNA replication starts, called the origin of replication. This allows the vector to replicate along with the host organism's DNA.
• Multiple cloning sites: 
• Vectors often have regions with many restriction enzyme recognition sites, known as multiple cloning sites or polylinkers. These sites allow easy insertion of DNA fragments for genetic engineering.
• Reporter genes: 
• Some vectors contain genes that produce easily detectable proteins or molecules, helping researchers monitor the presence or activity of the vector in the host organism.
• Size: 
• Vectors are usually smaller in size compared to the host organism's genome, making them distinguishable.

These characteristics make vectors useful tools for genetic engineering and help researchers identify and manipulate them within host organisms.

• Types of Plasmid Vector?

Here are the types of vectors explained in simple language:

• Plasmid Vectors: Plasmids are tiny loops of DNA found in bacteria. Scientists use them as carriers to transport new DNA into bacteria for genetic experiments.
• Viral Vectors: These are made from viruses that infect cells. Scientists modify these viruses to carry new DNA into cells for gene therapy or research.
• Bacteriophage Vectors: Bacteriophages are viruses that infect bacteria. Scientists can use them to deliver new DNA to bacteria.
• Cosmid Vectors: Cosmids are like plasmids but can carry larger pieces of DNA. They're used when scientists need to transport bigger chunks of DNA.
• Phage Lambda Vectors: These are vectors made from a specific kind of virus that infects bacteria. They're useful for cloning large pieces of DNA.
• Yeast Artificial Chromosome (YAC) Vectors: YAC vectors are used to clone large pieces of DNA in yeast cells. They mimic natural yeast chromosomes.
• Bacterial Artificial Chromosome (BAC) Vectors: BAC vectors are similar to YAC vectors but used in bacteria instead of yeast. They're good for cloning very large DNA pieces.
• Plant Transformation Vectors: These vectors are specially designed to transfer new DNA into plant cells for genetic modification.

These different types of vectors help scientists to transfer DNA into cells for various purposes, like studying genes or creating genetically modified organisms.

• You just told me the most abundantly used vector is a plasmid, can you tell me about it?

Plasmids are small, circular DNA molecules found naturally in bacteria. In genetic engineering, scientists harness these plasmids to carry and deliver foreign DNA into bacterial cells for various purposes. Here's a breakdown of plasmid vectors:

• Structure: Imagine a plasmid as a tiny, circular DNA package. It's like a small, extra piece of genetic material that bacteria can carry around.
• Origin of Replication (ori): Think of the origin of replication (ori) as the plasmid's "start" button. It tells the bacterial cell machinery to copy the plasmid when the cell divides, ensuring each new cell gets its own copy.
• Selectable Markers: Picture the plasmid carrying a special "survival badge." For example, if the plasmid has a gene for resisting an antibiotic like ampicillin, bacteria that grab this plasmid can survive when grown in the presence of ampicillin.
• Multiple Cloning Sites (MCS): Think of the multiple cloning sites as a puzzle board with many different shaped slots. Researchers can pick the right slot to fit their DNA puzzle piece and easily insert it into the plasmid.
• Promoters and Regulatory Elements: Imagine the plasmid having traffic lights (promoters) and traffic signs (regulatory elements). They control when and how much a gene on the plasmid gets "expressed" or used by the bacterial cell.
• Size Limitations: Consider the plasmid as a tiny suitcase. While it can carry some extra DNA, it has limited space. Smaller plasmids can only carry a few small DNA pieces, while bigger ones can handle larger chunks.

So, plasmid vectors are like genetic toolkits that scientists use to add new DNA to bacteria. They're essential for many experiments, allowing researchers to manipulate genes and study how they work in living cells.

• Can you tell me, when it was invented and how it was named?

Certainly! The concept of vectors in genetic engineering emerged gradually alongside the development of recombinant DNA technology. Initially, vectors were recognized in the context of bacterial genetics with the discovery of plasmids in the 1950s and 1960s. Plasmids, small circular DNA molecules found in bacteria, served as carriers of genetic material and were essential for antibiotic resistance. As scientists began manipulating DNA in vitro in the early 1970s, the term "vector" gained prominence in molecular biology. Borrowed from mathematics and physics, "vector" signified a carrier or transporter, reflecting its role in transferring genetic material between organisms. Early vectors used in genetic engineering were often derived from natural genetic elements like plasmids and bacteriophages, modified to carry foreign DNA into host cells for replication and expression. Over time, the terminology surrounding vectors became more formalized, categorizing different types based on their structure, function, and application, including plasmid vectors, viral vectors, and artificial chromosomes. Today, vectors play a central role in genetic engineering, facilitating the manipulation and transfer of genetic material for various purposes, from basic research to biotechnological applications.

• Give me two examples of plasmid vectors?