Decoding Bacterial Artificial Chromosome (BAC)    

Bacterial Artificial Chromosomes (BACs) are DNA constructs, based on a functional fertility plasmid (F-plasmid). They facilitate the transforming and cloning of DNA fragments in bacterial cells, specifically E. coli.    

BACs are commonly used in various fields, including genetics, gene cloning, genomic research, and molecular biology. They find their use in multiple fields as they can carry large DNA inserts.   

The number typically ranges between 100 to 300 kilobases (Kb), significantly larger than other cloning vectors such as plasmids. This blog will make you aware of Bacterial Artificial Chromosome Notes – continue reading.         

What Are The Features Of Bacterial Artificial Chromosomes?     

The key features of Bacterial Artificial Chromosomes (BACs) are as follows: 

• Replication Origin: BACs carry large DNA constructs derived from the F-plasmid. It enables the BAC to replicate within the bacterial host cells. The origin of replication ensures that the BAC is maintained as a single-copy or low-copy plasmid. In this way, the likelihood of recombination and instability is reduced.  
  
• Selectable Markers: DNA construct or BAC vectors consist of selectable markers (e.g., antibiotic resistance genes). These vectors facilitate the selection of bacteria that have taken up the BAC. They allow for the selection of successfully transformed cells.    
  

• Par Genes: BAC gets properly partitioned into the daughter cells during cell division. It helps maintain a low copy number (LCN) per cell.  
  

• Multiple Cloning Site (MCS): Also known as Polylinker, characterized by a region containing multiple unique restriction sites where foreign DNA fragments can be inserted.    

• Large Insert Capacity: Vectors of the BAC accommodate larger DNA fragments. This makes them suitable for cloning large genes, gene clusters, or entire genomes.   

Applications Of Bacterial Artificial Chromosomes   

• Genomic Libraries: The use of Bacterial Artificial Chromosomes helps create genomic libraries. These libraries contain a collection of DNA fragments, and the entire genome of an organism is fragmented and cloned into BAC vectors. Genomic libraries facilitate processes like genome mapping, sequencing, and analysis.      

• Genome Sequencing: BACs play a very important role in the Human Genome Project. Apart from that, it also supports other activities like large-scale sequencing and physical mapping. This enables the sequencing of large DNA fragments, managing the complexity of large genomes, and assembling complete genomes.       

• Functional Genomics: Bacterial Artificial Chromosomes (BACs) find their use in functional genomics to understand gene function. Moreover, it also supports gene regulation by allowing the manipulation and analysis of large functional genomic regions.     

• Transgenic Models: BACs help generate transgenic models (animals and plants) by introducing large DNA fragments into organisms. The DNA fragments contain genes and regulatory elements which provide a more comprehensive representation of gene function.    

Advantages Of Bacterial Artificial Chromosomes (BAC) 

Bacterial Artificial Chromosomes (BACs) provide several different advantages, making them powerful tools in genetic and genomic research. BAC offers advantages in genetic research, enhancing their capacity to carry large DNA fragments, stability, ease of manipulation, and applications in various genomic studies.      

• Large Insert Capacity: BACs have large DNA insert accommodation, typically ranging from 100 to 300 kilobases (Kb). In comparison to the other vectors like plasmids and cosmids, BACs have significantly larger capacity. Due to this ability, BACs are ideal for cloning large genes, gene clusters, and entire genomic regions.    

BACs facilitate the cloning of large DNA fragments. It allows for the preservation of complete gene sequences, including regulatory elements and non-coding regions. BAC facilitates more comprehensive genetic research.      

• Application in Genomic Libraries: BACs are very helpful in processes like genome mapping as well as sequencing. They help create genome libraries to facilitate these processes. BACs also support other large-scale genomic initiatives. 

Apart from this, BAC enables physical mapping of genomes, which helps to establish the order. It also allows to set distance between genes or other significant genomic features.  

• Stability: The BAC system maintains the assembly of a full-length copy of the viral genome in BAC plasmids. These are maintained at a low copy number (LCN) within bacterial cells. This lowers the risk of recombination and mutation of the inserted DNA. In this way, the BACs remain stable.   

It is essential to stabilize the BACs, its stability helps maintain the integrity of large genomic fragments over long periods. Besides, it also ensures consistent and reliable propagation of cloned DNA, essential for reproducible research results.  

• Ease of Manipulation: Selectable markers such as antibiotic resistance genes are present in BAC vectors. This facilitates the ease of selection of successfully transformed bacterial cells.  

BACs can be processed with recombinant techniques. The use of standard molecular biology techniques helps manipulate BACs, making them accessible tools to be used in research.        

• Functional Genomics: The study of gene function involves BACs, as it includes large genomic fragments in bacterial cells. The researchers analyze the DNA fragments, and the information is utilized for gene expression, regulation, and interaction.BACs generate transgenic animals and plants, which supports researchers in studying gene function and regulation. The study is based on a more complex and physiologically relevant context.  
  
  
• Supports Disease Research: BACs are employed to introduce large genomic regions into model organisms. This allows the detailed and complex study of human diseases and the development of therapeutic strategies to manage them.    

Role Of BACs In Genetic Testing  

Bacterial Artificial Chromosomes (BACs) have a crucial role to play in genetic testing and research. It provides a means to copy, store, and analyze large fragments of DNA. Let us have a look at the function of BACs in gene testing: 

• Gene Mapping and Sequencing: BAC offers cloning of large DNA fragments, along with sequencing, mapping, and genome assembling.   

• Functional Genomics: BACs facilitate the studies of genomic context, which allows researchers to understand genetic diseases and develop treatment strategies.  

• Human Genome Project: BACs allow systemic processing and sequencing of the human genome. 

• Genetic Disorder Identification: The risk of genetic diseases can be determined through screening of BAC libraries.  

• Comparative Genomic Hybridization (CGH): This process helps identify chromosomal abnormalities.  

This makes BACs essential tools in genetic testing and research.  BACs provide detailed analysis of large genomic regions. They improve the understanding of genetics and facilitate the development of diagnostic and therapeutic strategies.    

Conclusion  

Bacterial Artificial Chromosomes (BACs) have a significant role in genetic research and testing. It enables the cloning, analysis, and manipulation of large DNA fragments.   

BACs facilitate large-scale projects like the Human Genome Project, disease gene identification, and cancer research. Thus, it provides a stable and accurate means of studying complex genomic regions.