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 species. Please keep me posted! Thanks! haibo //cheers 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 > those > > paralogs which arose from a duplication after the speciation event are > called > > 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? > > Hi, > Good question! Maby someone on the sequence searching mailing list can > help answer, > > http://bioinformatics.org/mailman/listinfo/ssml-general > > > I know of some work trying to uncover 'lineage specific gene expansion' > by Eugene > 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, simply > 'best hits' between genome 1 and 2. > > Although I understand the definition of orthology and paralogy, I find > the concepts > 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'? > > Cheers, > > > 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 > https://bioinformatics.org/mailman/listinfo/bio_bulletin_board > ========================================================= Haibo Zhang, PhD student Computational Biology, NJIT & Rutgers University Center for Applied Genomics, PHRI http://afs13.njit.edu/~hz5