Dear Joyce

BLAST is a tool that produce the pairwise sequence local alignment. Originally, speaking local alignments reveals the functional significant characters like catalytic site, receptor binding site, promoter sequence etc., But BLAST produce a bigger local sequence. By using other specific tools we can minimize the sequence length. You can find the sequence similarity by using BLAST (expressed in percentage).

E (): value (expectation value)should be always low. i.e., E value is 0.5 means you are expecting an identical 50 sequences (like the sequence what you have) out of 100 sequences in a database. If an E value is 0.0001 means you are expecting only 1 identical sequence out of 10,000 sequence present in a database

Thanks a lot.

Hope this will help me.

hello this is field which is combination of Biology,Computer,Statistics,maths.....

In that field we don't want that you have knowledge about the a particular subject.In our field mostly bioinformatist

what ever work biotechnologist can do we can also do on computer using different different programs to do that,But what ever work we do is mostly the prediction.....In these we can work on micrroarray,protein str prediction,docking,gene expression analysis and much more....

Ya ofcourse what Bhakti Ekbote said right but here one more thing should be considered to move further, i.e you have to know little bit about DNA, RNA and Proteins and their basics or fundamental concepts that we can apply with computer algorithms. This is my small suggestion!!!! Thank you

I am also knew to this field and am wondering which is the best way to present blast results? and what is the significance of e value?

Dear Joyce

BLAST is a tool that produce the pairwise sequence local alignment. Originally, speaking local alignments reveals the functional significant characters like catalytic site, receptor binding site, promoter sequence etc., But BLAST produce a bigger local sequence. By using other specific tools we can minimize the sequence length. You can find the sequence similarity by using BLAST (expressed in percentage).

E (): value (expectation value)should be always low. i.e., E value is 0.5 means you are expecting an identical 50 sequences (like the sequence what you have) out of 100 sequences in a database. If an E value is 0.0001 means you are expecting only 1 identical sequence out of 10,000 sequence present in a database

Bioinformatist must know tools like BLAST,FASTA,CLUSTAL W,EMBOSS,Swiss Model,...there is also lots of tools available in Bioinformatics which also use widely.

Databases are NCBI,EMBL,DDBJ,Uniprot,etc

And Languages like c,c++,Java,Perl and Pythen......

Bioinformatist must know abt the DNA,RNA,protein...

Bioinformatician should know the basic of protein structure prediction...... eg: homology modelling --http://salilab.org/modeller/-

Hey any one explain more abt e value

BLAST is a Local Alignment Search. So the alignment that you obtained is due to chance. The e-value (or Expect value) is a parameter that describes the number of hits one can "expect" to see just by chance when searching a database of a particular size. It decreases exponentially with the Score (S) that is assigned to a match between two sequences. Essentially, the e-value describes the random background noise that exists for matches between sequences.

The smaller the e value the alignment is not due to chance. If the e value is very high then the alignment is by chance. So in blast results we always try to take results with e value close to zero.

The e-value is used as a convenient way to create a significance threshold for reporting results. When the e-value is increased from the default value of 10, a larger list with more low-scoring hits can be reported. On the other hand, a lower e-value will result in a shorter list with more quality hits.

Thanks for that it will helpful for me......now am m asking question which will silly for some one but m really dont know what is hits....pls anyone know tell me..

Each match found during blast is called as a hit.

K thank you so much....

Hello you explain about e value...but in that i dont understand is "chance".....so will u expalin me what is chance?

"chance" can mean the comparison of (i) real but non-homologous sequences; (ii) real sequences that are shuffled to preserve compositional properties or (iii) sequences that are generated randomly based upon a DNA or protein sequence model

Join "ibab"

W8 is that?