A SHORT NOTE ON SEQUENCED TAG SITES.(A TYPE OF PHYSICAL MAPPING OF GENOME).

1. WEL COME..
Short note on sts a type physical mapping of genome

2. SEQUENCED TAGED SITES (STS)
 What is sequenced tag sites?
It is a short DNA sequence, generally between
100 to 500 bp in length occurring only once in the
chromosome or genome under study.
OR
A UNIQUE DNA sequence

4. TO BE CALLED AS STS…….
 Requirements…..
1. ITS SEQUENCE MUST BE KNOWN..
2. THE DNA SEQUENCE MUST HAVE LOCATION
IN THE CHROMOSOMES.BEING STUDIED.

5. STS
Expressed
sequence tags.
Simple sequence
length
polymorphs.(SSL
Ps)
Random genomic
sequences.

6.  Expressed sequence tags:
It is the sequence obtained by the analysing the
cDNA.
 Now cDNA is obtained by mRNA,that is by using
reverse transcriptase enzyme. there by knowing the
gene which codes for a particular proteins.
 Thus coding sequences which are unique hence
used as STS.

7. SIMPLE SEQUENCE LENGTH
POLYMORPHS.(SSLPS)
 SSLPs are array of repeating sequences, that
display length of variations, different allele
containing different numbers of repeat units. Unlike
the RFLP SSLPs can be multi allelic as each
SSLPs can have a number of different variable
length..

8. Simple sequence
length
polymorphs.(SSLPs)
Minisatellite
Microsatellite

9.  Minisatellite : also known as varaible numbers of
tandem repeats.(VNTRs) in which repeat units are
upto 25 bp
 Microsatelite or simple tandem repeats (STRs): In
which repeat units are upto 13bp or less.

10. Minisatellite Microsatellite
It has repeating units of 25 bp It has repeating units 13 bp
Its disrtribution towards telomeric
sites of the chromoses.
Distributed throughout the
chromoses
It is not frequently used Frequently used
Handling of these markers become
difficult for pcr machine
i.e basepairs are in kilo
Easily handled by pcr machine i.e its
in total of hundred bases…

11. MICROSATELLITE……………

13. MINISATELLITE…..

15.  Random genomic sequences:These are obtained
by sequencing random piecis of cloned genomic
DNA or simply by down loading the sequences that
have deposited in the data bases

16. Fragment of
DNA for STS
mapping
A clone
library
Radiation
hybrids.

17. RADIATION HYBRIDS:
CELLS
(CHROMOSOMES)
BREAKDOWN OF
CHROMOSOMES.
HYBRIDIZATION.
IRRADIATION.

19. A CLONE LIBRARY:

21. THANK U.