sequenced taged sites (sts)

WEL COME..

Short note on sts a type physical mapping of genome

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

TO BE CALLED AS STS…….

Requirements…..

1. ITS SEQUENCE MUST BE KNOWN..

2. THE DNA SEQUENCE MUST HAVE LOCATION

IN THE CHROMOSOMES.BEING STUDIED.

STS

Expressed sequence tags.

Simple sequence length

polymorphs.(SSLPs)

Random genomic sequences.

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.

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..

Simple sequence length

polymorphs.(SSLPs)

Minisatellite

Microsatellite

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.

Minisatellite MicrosatelliteIt 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…

MICROSATELLITE……………

MINISATELLITE…..

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

Fragment of DNA for STS

mapping

A clone library

Radiation hybrids.

RADIATION HYBRIDS:

CELLS

(CHROMOSOMES)

BREAKDOWN OF CHROMOSOMES.

HYBRIDIZATION.

IRRADIATION.

A CLONE LIBRARY:

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