From: Hutter Pierre <pierre.hutter@XXXX>
To: ''Gillian Millburn (Genetics)'' <gm119@XXXX>
Subject: RE: comments on the RAB9D gene
Date: Mon, 25 Jul 2005  18:29:24  \+0200
Dear Gillian,
I clarified the site of insertion of the PBac{WH}Rab9Df06390 transposon
(Thibault et al. 2004)in Rab9D by genomic sequencing, which placed it at
the TTAA target site at nucleotides 23-26 (from the A of the start codon of
Rab9D). In D. melanogaster Hmr1 (hybrid rescuing mutant) flies, the Rab9D
gene contains five nucleotide changes, which lead to four amino acid
substitutions. Interestingly, all four replacements correspond to amino
acids present at the same sites in proteins encoded by some of the five
paralogs
of Rab9D. Moreover, the Rab9D gene has considerably diverged between D.
melanogaster
and its close relative D. mauritiana, whose Rab9D sequence was reported last
year under GenBank accession number AY830113. I also observed that Rab9D
appears to have evolved under particularly strong positive Darwinian
selection, as shown by pairwise comparisons of Ka/Ks ratios, which are
higher than 2 between Rab9D and its paralogs CG32670 or CG2885. It should
also be pointed out that no ortholog of Rab9D can currently be identified in
genomes from other arthropods,
suggesting that Rab9D and its three closest paralogs are unique to D.
melanogaster.
Thank you very much for your assistance.
Pierre Hutter, PhD, FAMH
Chef de la Division de Génétique Médicale
Institut Central des H&ocaret;pitaux Valaisans
Av.Grand-Champsec 86
1951 Sion. Switzerland
Phone: 027 603 4850
Fax: 027 603 4995
e-mail: pierre.hutter@XXXX