The thioredoxin/glutaredoxin family consists of small heat-stable proteins
that have a highly conserved CXXC active site and that participate in the r
egulation of many redox reactions. We have searched the human genome sequen
ce to find putative pseudogenes (non-functional copies of protein-coding ge
nes) for all known members of this family. This survey has resulted in the
identification of seven processed pseudogenes for human Trx1 and two more f
or human Grx1. No evidence for the presence of processed pseudogenes has be
en found for the remaining members of this family. In addition, we have bee
n unable to detect any non-processed pseudogenes derived from any member of
the family in the human genome. The seven thioredoxin pseudogenes can be d
ivided into two groups: Trx1-psi2, -psi3, -psi4, -psi5 and -psi6 arose from
the functional ancestor, whereas Trx1-psi1 and -psi7 originated from Trx1-
psi2 and -psi6, respectively. In all cases, the pseudogenes originated afte
r the human/rodent radiation as shown by phylogenetic analysis. This is als
o the case for Grx1-psi1 and Grx1-psi2, which are placed between rodent and
human sequences in the phylogenetic tree. Our study provides a molecular r
ecord of the recent evolution of these two genes in the hominid lineage.