[BiO BB] protein identity
philipp.pagel at cmp.yale.edu
Mon Oct 22 17:49:43 EDT 2001
On Mon, Oct 22, 2001 at 01:42:08PM -0700, nabula easter wrote:
> When two proteins are 98-99% identical, what is the
> relationship associated between them.
> Can we call those proteins as very close homologues !
> or that 2% difference between then is due to sequence
> errors at Nucleic acid level.
> At nucleic acid level they would be 94% identical and
> we can say a sequnce error!
That depends on how reliable your sequence is. If your sequence data is
reliable you have a close homologue. What exactly that means depends on the
source of the DNA and functional data:
- In the same species you might be looking at different isoforms - maybe
with functional differences.
- If it's from different species it is likely that they are functionally
the same thing.
- The proteins might also have significantly different functions although
you would expect less identity.
So they could be orthologs, paralogs, isoforms or just sequencing errors. Was
this a hypothetical question or are you talking about something you are working
on right now? If it's a real-world question you may want to tell us where the
sequence data came from and we can narrow it down some more.
cu and hope it helps
Dr. Philipp Pagel
Department of Cellular and Molecular Physiology phone: (203) 785-6835
SHM, B117 fax: (203) 785-4951
333 Cedar ST
New Haven, CT 06520
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