Fosmids are low copy number cloning vectors this is a general insight to what fosmids are its history and applications

1. FOSMIDS AS
CLONING VECTORS
SHRI HARI PRASAD
M.Sc. Plant Biotechnology
Kerala Agricultural University

2. Fosmid
Fosmid is a low copy number vector constructed by combining
the features of F plasmid, and cos site and it also has parA
and par B genes.

3. ■ Fosmids are similar to cosmids.
■ Based on the bacterial F-plasmid.
■ Simon and co-workers (1992) first developed F-factor
based vector named as pFOS.
■ Fosmid = ori(F plasmid) + λ cos site.
■ Inserts of up to 40 kb in size.

4. ■ The cloning vector is limited, as a host (usually E.coli).
■ Low copy number in the host (eg.,1 fosmid).
■ Higher stability than vectors with relatively higher copy
numbers, including cosmids.
■ Useful for constructing stable libraries from
complex genomes.
■ Fosmids have high structural stability and have been
found to maintain human DNA effectively even after 100
generations of bacterial growth.

6. FUNCTIONAL ELEMENTS
■ OriT (Origin of Transfer): The sequence which marks the
starting point of conjugative transfer.
■ OriV (Origin of Replication): The sequence starting with
which the plasmid DNA will be replicated in the
recipient cell.
■ tra -region (transfer genes): Genes coding the F-Pilus
and DNA transfer process.
■ IS (Insertion Elements): so-called "selfish genes"
(sequence fragments which can integrate copies of
themselves at different locations).

8. FOSMID LIBRARY
■ The first step in sequencing entire genomes.
■ Fosmid library is ideal because of its stability and
limitation of one plasmid per cell.
■ By limiting the number of plasmids in the cells the
potential for recombination is decreased, thus
preserving the genome insert.

10. Applications
■ 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.
■ Cytological markers for individual chromosome
identification and fluorescent in situ hybridization

11. THANK YOU