Hi,
Actually paralogs are just duplicated genes. If the duplication event
has happened before speciation of two (or more) species you are
investigating, these species can share the paralogs.
See the following paper for the original definition.
Fitch, WM "Distinguishing homologous from analogous proteins"
Syst. Zool. 19(2), 99-113 (1970).
He may have recently published a paper about this issue on TIG.
ir ka wrote:
> Could somoine give me the correct definition of paralogs, preferably with
> a good reference ? The literature that I have read up to know is not clear
> whether paralogs are always defined within one species.