A Bkm-associated human y-chromosomal DNA is conserved and transcribed in the testis of mouse

A highly conserved human gene encoding a novel member of WD-repeat family of proteins (WDR13)

We have identified and characterized a novel member of the WD-repeat motif gene family, WDR13, which contains 9 exons and 8 introns. The gene has been mapped to the genomic locus Xp11.23 by fluorescent in situ hybridization and in silico mapping. Sequence analysis has revealed a continuous open reading frame (ORF) encoding for 485 amino acids with six WD motifs. The expression of this gene has been detected in all the tissues analyzed with significantly varied expression levels among the tissues studied. Analysis of EST clones from various tissues, showing significant homology to WDR13, has identified two spliced variants. The transcription start point has been mapped. Promoter analysis has identified high activity in the 5' UTR, which interestingly showed a testis-specific activity in the transgenic animals studied. The subcellular localization of the WDR13 protein in the nucleus suggests that it may also have a regulatory role in nuclear function along with protein-protein interaction like other members of the WD family of proteins.

Different genomic evolutionary rates in the various reptile lineages

Although Reptiles occupy a strategic position among terrestrial vertebrates, studies of the composition and evolution of their genome are scarce. The cytogenetic analysis of nearly 1400 species evidenced different karyotypical evolutionary rates and different G-banding structures in turtles and crocodiles on the one hand and squamates on the other. A similar dichotomy was also identified through the study of the quantitative and compositional characteristics of the genome. The different evolutionary rates of chromosome morphology and genome size and composition and the diversification of coding and non-coding sequences bear an interesting relationship to the number of extant species and the extinction rates of the reptilian orders and suborders studied, suggesting a large role for such different evolutionary rates in the phylogenesis of this class. The different molecular and structural organisation of chromosomes could be an important, though by no means the sole, factor affecting the genome's evolutionary rate.