A new split of the Hox gene complex in Drosophila: relocation and evolution of the gene labial.

Hox genes encode transcription factors involved in the specification of segment identity in the early metazoan embryo. These genes are usually clustered and arranged in the same order as they are expressed along the anteroposterior body axis. This conserved genomic organization has suggested the existence of functional constraints acting on the genome organization.

Low occurrence of gene transposition events during the evolution of the genus Drosophila.

The role played by gene transpositions during the evolution of eukaryotic genomes is still poorly understood and indeed has been analyzed in detail only in nematodes. In Drosophila, a limited number of transpositions have been detected by comparing the chromosomal location of genes between different species. The relative importance of gene transposition versus other types of chromosomal rearrangements, for example, inversions, has not yet been evaluated.

Origin and evolution of a new gene expressed in the Drosophila sperm axoneme.

Sdic is a new gene that evolved recently in the lineage of Drosophila melanogaster. It was formed from a duplication and fusion of the gene AnnX, which encodes annexin X, and Cdic, which encodes the intermediate polypeptide chain of the cytoplasmic dynein. The fusion joins AnnX exon 4 with Cdic intron 3, which brings together three putative promoter elements for testes-specific expression of Sdic: the distal conserved element (DCE) and testes-specific element (TSE) are derived from AnnX, and the proximal conserved element (PCE) from Cdic intron 3.

Chromosomal elements evolve at different rates in the Drosophila genome.

Recent results indicate that the rate of chromosomal rearrangement in the genus Drosophila is the highest found so far in any eukaryote. This conclusion is based chiefly on the comparative mapping analysis of a single chromosomal element (Muller's element E) in two species, D. melanogaster and D.