[BiO BB] orthologs vs in-paralogs
dmb at mrc-dunn.cam.ac.uk
Fri Sep 5 08:07:11 EDT 2003
> This is a good question, please drop me a note if you guys get some answers.
> For all I know, besides the homolog part, the key difference is that ortholog is
> same function in different species, while paralog is different function in same
Yup, I know this definition, but it doesn't address the idea or redundancy within a
genome. This is (apparently) a big issue for functional genomics.
> Please keep me posted!
> Quoting Dan Bolser <dmb at mrc-dunn.cam.ac.uk>:
>> Phil Luo said:
>> > Dear all,
>> > As we know ,there are two kinds of homolog, ortholog and paralog.
>> Genes in two
>> > species that have directly evolved from a single gene in the last
>> common ancestor
>> > are called orthologs. A set of homologous genes that have diverged
>> from each other
>> > as a consequence of genetic duplication are called paralogs. Sometime
>> > paralogs which arose from a duplication after the speciation event are
>> > in-paralogs.
>> > My question is how to distinguish the in-paralogs from orthologs.
>> Which one is
>> > supposed to be more similar, in-paralogs or orthologs?
>> Good question! Maby someone on the sequence searching mailing list can help
>> I know of some work trying to uncover 'lineage specific gene expansion' by
>> Koonin (sp?) at the NCBI. That sounds a bit like the in-paralogues you describe.
>> Also he and coworkers define an algorithm for predicting orthologous pairs,
>> 'best hits' between genome 1 and 2.
>> Although I understand the definition of orthology and paralogy, I find the
>> a bit confusing. I don't know what information you loose by simply talking about
>> gene families, and ignoring the within / between genome distinction.
>> At some level does't ortholog mean 'same gene', and paralog mean 'copy'?
>> > Best regards,
>> > Phil
>> > ---------------------------------
>> > Do you Yahoo!?
>> > Yahoo! SiteBuilder - Free, easy-to-use web site design software
>> BiO_Bulletin_Board maillist - BiO_Bulletin_Board at bioinformatics.org
> Haibo Zhang, PhD student
> Computational Biology, NJIT & Rutgers University
> Center for Applied Genomics, PHRI
More information about the BBB