Evo–Devo

Evolution of yellow gene regulation and pigmentation in Drosophila.Wittkopp, P. J. et al. Curr. Biol. 12, 1547–1556 (2002)

One goal of evolutionary developmental biology is to understand the molecular-genetic basis of phenotypic evolution. A useful system for such studies is the evolution of the pigmentation pattern in the Drosophila lineage. By using transgenic flies that carry a heterologous yellow (melanin-encoding) gene, the authors show that changes in yellow expression in closely related species have resulted from changes in both cis-regulatory regions and trans-acting factors. The different yellow expression patterns can also be attributed to evolutionary changes in other genes.

Developmental biology

Hedgehog-mediated patterning of the mammalian embryo requires transporter-like function of Dispatched.Ma, Y. et al. Cell 111, 63–75 (2002)

Mouse Dispatched homolog1 is required for long-range, but not juxtacrine, Hh signaling.Caspary, T. et al. Curr. Biol. 12, 1628–1632 (2002)

Signalling by the Hedgehog (Hh) family of proteins is required to pattern many vertebrate and invertebrate tissues in a concentration-dependent manner. In flies, the long-range action of Hh proteins is thought to occur through the ability of Dispatched (Disp), a transmembrane protein, to release Hh from the outer membrane of Hh-producing cells. Ma and colleagues show that this function is conserved in mouse and that DispA, a mouse disp homologue, is required for all mouse Hh patterning functions. In a screen for genes required for the ventral patterning of the neural tube, Caspary et al. identified Disp1, a second mouse disp homologue, and have shown that it is required for long-, but not short-, range Hh signalling.

Functional genomics

Gene expression during the life cycle of Drosophila melanogaster.Arbeitman, M. N. et al. Science 297, 2270–2275 (2002)http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12351791&dopt=Abstract

This paper reports the microarray-based transcriptional profiling of 4,028 wild-type Drosophila genes, assayed at 66 sequential time points during the organism's life cycle. Expression was also assayed in mutant flies that lack germline and eye tissue to refine expression data for these tissues. Many dynamic gene-expression changes are reported that correlate with Drosophila's development, maturation and sex. Hierarchical clustering analyses also provide new information on gene function and on the components of pathways and complexes, as these analyses clustered many genes of unknown function with genes of known or predicted function.