Author: Patrick J. Babin
Position: Professor
Institution: Universite Bordeaux 1, France
E-mail: p.babin@gpp.u-bordeaux1.fr
Submitted Date: March 26, 2008
Published Date: April 1, 2008
This comment was originally posted as a “Reader Response” on the publication date indicated above. All Reader Responses are now available as comments.

Multiple genome alignments constitute a resource for identifying strings of genes that retain the ancestral order, i.e. conserved synteny blocks, which may be used for dissecting the orthologous/paralogous relationships with genes from relatively taxonomically distant species. Genomic elements in compared species that descend from the same ancestral element in the genome of their last common ancestor may be considered orthologous. By using a highly sensitive similarity search algorithms, Brawand et al., identified vitellogenin pseudogenic coding sequence remnants in mammalian genomes, including human, synthenic to chicken vitellogenin genes. This finding is nicely complementary to the identification of a vitellogenin gene cluster (VGC) in oviparous vertebrate genomes that was established prior to the divergence of ray-finned fish and tetrapods [1]. It is interesting that indirect arguments support in both studies the presence of a functional VTG gene in the platypus genome. While these two studies gave data on the life and death of the VGC, additional data are now needed in early-branching vertebrate genomes to establish when this cluster appeared.

1) Babin PJ (2008) Conservation of a vitellogenin gene cluster in oviparous vertebrates and identification of its traces in the platypus genome. Gene 413(1-2): 76-82 (doi:10.1016/j.gene.2008.02.001, PMID: 18343608)