We present here a draft genome sequence of the red jungle fowl, Gallus gallus. Because the chicken is a modern descendant of the dinosaurs and the first non-mammalian amniote to have its genome sequenced, the draft sequence of its genome--composed of approximately one billion base pairs of sequence and an estimated 20,000-23,000 genes--provides a new perspective on vertebrate genome evolution, while also improving the annotation of mammalian genomes. For example, the evolutionary distance between chicken and human provides high specificity in detecting functional elements, both non-coding and coding. Notably, many conserved non-coding sequences are far from genes and cannot be assigned to defined functional classes. In coding regions the evolutionary dynamics of protein domains and orthologous groups illustrate processes that distinguish the lineages leading to birds and mammals. The distinctive properties of avian microchromosomes, together with the inferred patterns of conserved synteny, provide additional insights into vertebrate chromosome architecture.
We have sequenced and annotated the genome of fission yeast (Schizosaccharomyces pombe), which contains the smallest number of protein-coding genes yet recorded for a eukaryote: 4,824. The centromeres are between 35 and 110 kilobases (kb) and contain related repeats including a highly conserved 1.8-kb element. Regions upstream of genes are longer than in budding yeast (Saccharomyces cerevisiae), possibly reflecting more-extended control regions. Some 43% of the genes contain introns, of which there are 4,730. Fifty genes have significant similarity with human disease genes; half of these are cancer related. We identify highly conserved genes important for eukaryotic cell organization including those required for the cytoskeleton, compartmentation, cell-cycle control, proteolysis, protein phosphorylation and RNA splicing. These genes may have originated with the appearance of eukaryotic life. Few similarly conserved genes that are important for multicellular organization were identified, suggesting that the transition from prokaryotes to eukaryotes required more new genes than did the transition from unicellular to multicellular organization.
Fifty human muscle biopsies were examined for histochemical localization of acetylcholinesterase (AChE) activity. Six normal muscle samples had AChE at the myoneural junctions and around the periphery of many fibers. The AChE within the sarcoplasm itself was found in only a few atrophied fibers. However, 21 of 44 biopsies of abnormal muscles had sarcoplasmic AChE in more than 10% of their fibers. Such cases included Duchenne, limb-girdle and facio-scapulo-humeral dystrophy, neurogenic and spinal muscle atrophy, spinal cord injury, peripheral nerve injury, Schwartz-Jampel syndrome and myasthenic syndrome. Sarcoplasmic AChE is found in embryo muscle and usually declines after birth. It appears after denervation in the chicken but not the rat and remains in muscles of chickens with an inherited muscular dystrophy. The results of the human muscle study support the idea that in the human, as in the chicken, interruption of a neurally-mediated regulation of AChE results in the reappearance of high AChE activity in the sarcoplasm of the muscle fibers.
Fifty-nine biopsies of human muscle, 53 of them abnormal, 6 normal, were studied for the histochemical localization of acetylcholinesterase (AChE) using frozen sections and light microscopy. In addition to AChE which was found at the myoneural and myotendon junction, specific staining was found around the periphery of many fibers from normal and abnormal muscles. Moreover, AChE activity was found to be high in the sarcoplasm of more than 10% of the fibers from 28 biopsies of abnormal muscle including cases of hemiplegia, spinal cord injury, denervation and neuropathy, infantile spinal muscle atrophy, Duchenne, limb-girdle and facioscapulohumeral dystrophies, Schwartz-Jampel syndrome and a myasthenic syndrome. Of the muscles from experimental animals examined, only the Rhesus monkey exhibited AChE around the periphery of the fibers, and only the dystrophic chicken and not the dystrophic mouse or hamster, showed extensive sarcoplasmic AChE. Histograms of muscle fiber diameters indicated that AChE in the sarcoplasm was associated with fibers of all sizes, depending on the nature of the disorder examined. Fibers containing AChE were smaller than unstained fibers in dystrophic chicken muscle. The results suggest that in the human, sarcoplasmic AChE is reversibly repressed during muscle maturation and that its mode of regulation by motor neurons is similar to that found in the chicken.
