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bac fosmid

Cepham Life Sciences provides high quality Fosmid library construction services to customers worldwide. Our advanced technologies and highly experienced scientists are available to assist you in all aspects of DNA extraction and shearing, vector construction, infection and QC analysis etc. Our goal is to provide you with the high-quality and most affordable Fosmid library construction services to ensure your satisfaction in a timely and professional manner.

Fosmid library construction services

Fosmids are similar to Cosmids, but are based on the bacterial F-plasmid. Fosmids are commonly used for preparing genomic libraries when a uniform insert size is desired. Fosmid libraries can be applied in whole genome physical map construction, the studies of gene function, gene expression and gene regulation. It is also a useful tool in map-based cloning of an important gene and the analysis of gene consistency. As a leading supplier in Fosmid library construction services, Cepham Life Sciences is committed to providing you the most affordable Fosmid library construction services with the fastest turnaround time to satisfy your downstream needs.


  • Construction of whole genome physical maps.
  • Research of gene function and gene expression regulation.
  • Map-based cloning of genes conferring important traits.
  • Gene structure and function analysis.


  • Guaranteed genome coverage.
  • High uniformity – the size of the insertion is all around 40kb.
  • High stability – single copy in the host bacteria because of the insertion of F-factor.
  • Competitive prices.
  • Fast turnaround time

Cepham Life Sciences offers Fosmid library construction services for your scientific research as follows:

  • DNA extraction and shearing.
  • Vector construction and infection.
  • Production of a Fosmid library.
  • Verification of library quality by randomly picking clones and determining insert sizes by restriction digest or DNA sequencing.

Fosmid library construction details

The key step for Fosmid library is preparation of inserts suitable for cloning into the Fosmid vector. To achieve true randomness of inserts, our Fosmid libraries are generated by random physical shearing of high molecular weight DNA (Please see Figure 1) using proprietary methods. A physically random sheared Fosmid library will dramatically reduce the costs for downstream application(s) such as end- sequencing and screening.

Figure 1: Physically sheared HMW DNA (Lane 1: un-sheared, Lanes 2-4: sheared).

Guaranteed high quality and genome coverage

Proprietary high efficiency cloning methods guarantee high quality and genome coverage that customers need. Obtained inserts sizes are always uniform and range within 35-45Kb (Please see below Figure 2). Our optimized methods are reliable, fast and cost effective.

Fosmid clones
Figure 2: Size determination of Fosmid clones.

Versatile Service package available

We offer non-arrayed libraries and arrayed libraries (colony picking, replicate plates, high density filters). We also offer customer library screening for positive clones. Copy control vector can be used for easy DNA purification from Fosmid clones.


[1] Liu C, Liu X, Lei L, et al. Fosmid library construction and screening for the maize mutant gene Vestigial glume 1. The Crop Journal, 2016, 4(1): 55-60.

[2] Hao D C, Yang L, Xiao P G. The first insight into the Taxus genome via Fosmid library construction and end sequencing. Molecular Genetics and Genomics, 2011, 285(3): 197-205.

[3] Lange C, Holtgr?we D, Schulz B, et al. Construction and characterization of a sugar beet (Beta vulgaris) Fosmid library. Genome, 2008, 51(11): 948-951.

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