BAC & Fosmid Library Construction

ig® Random Shear BAC Library Service:

ig® Unbiased BAC libraries without gaps, complete coverage, dramatically reduced finishing costs.

Even in the next-gen sequencing era, BAC (Bacterial Artificial Chromosome) clones are essential tools for genome research. Sequencing pooled BAC clones can simplify the assembly of a complex genome at the highest quality.

Because of the very large insert sizes, constructing BAC libraries are far more challenging than making typical, small-insert plasmid libraries. Even if successful, conventional BAC libraries are inherently biased and incomplete. Intact Genomics has developed novel random shear technologies that overcome many of these problems, producing more even, complete, and higher quality genomic libraries.

Using our unique random shear BAC colony technology, researchers can get even more accurate, better results.

A series of three images showing different types of animals.
A red streak is shown on the image.

Restriction digestion has significant limitations when making BAC libraries. The red arrow indicates undigestable megabase-size genomic DNA fragments from genomic regions, such as centromeres, highly repetitive sequences, telomeres, etc., that may completely lack recognition sites for common restriction enzymes (e.g., BamHI, EcoRI, and HindIII). These regions will not be represented in the BAC libraries and will result in gaps in the assembly. The solution for this problem is random shear BAC cloning. The same HMW genomic DNA can be randomly sheared into large fragments of 100-400 kb. Significantly, there is no megabase-size DNA left behind. In other words, the DNA from all genomic regions is randomly and equally sheared, which allows it to be cloned into BACs.

We created a random shear A. thaliana BAC library consisting of 7680 clones with an average insert size of 105kb. This is ~5x coverage of the genome. The library was screened with Overgo probes for some of the regions flanking known gaps to isolate individual randomly sheared BAC clones that span or reach into these gaps. The dashed lines represent the probe locations and the red lines represent the clones that were isolated using the probes. Now we can identify and span these gaps to sequence and assemble these previously difficult regions.

A diagram of the city skyline with different colors.

Conventional BAC Library Service also available for customer’ needs.

Fosmid Library Service:
Get the same unique advantages in a fosmid library, consistent average insert size at 40 kb.

A black and white photo of some random shear fosmids
A table with several different types of animal parts.

Other Genomic Services:

  • Custom vector construction
    Custom vector design for your research needs
  • Large-insert DNA cloning and manipulation
    Clone large DNA fragment(s) into BAC, Fosmid, or custom vector(s)
  • BAC engineering
    Custom BAC modification for your special requirements