Genomic sequencing has made it clear that a large fraction of the genes specifying the core biological functions are shared by all eukaryotes. Knowledge of the biological role of such shared proteins in one organism can often be transferred to other organisms. The goal of the Gene Ontology Consortium is to produce a dynamic, controlled vocabulary that can be applied to all eukaryotes even as knowledge of gene and protein roles in cells is accumulating and changing. To this end, three independent ontologies accessible on the World-Wide Web (http://www.geneontology.org) are being constructed: biological process, molecular function and cellular component.The accelerating availability of molecular sequences, particularly the sequences of entire genomes, has transformed both the theory and practice of experimental biology. Where once biochemists characterized proteins by their diverse activities and abundances, and geneticists characterized genes by the phenotypes of their mutations, all biologists now acknowledge that there is likely to be a single limited universe of genes and proteins, many of which are conserved in most or all living cells. This recognition has fuelled a grand unification of biology; the information about the shared genes and proteins contributes to our understanding of all the diverse organisms that share them. Knowledge of the biological role of such a shared protein in one organism can certainly illuminate, and often provide strong inference of, its role in other organisms.Progress in the way that biologists describe and conceptualize the shared biological elements has not kept pace with sequencing. For the most part, the current systems of nomenclature for genes and their products remain divergent even when the experts appreciate the underlying similarities. Interoperability of genomic databases is limited by this lack of progress, and it is this major obstacle that the Gene Ontology (GO) Consortium was formed to address.

The fly Drosophila melanogaster is one of the most intensively studied organisms in biology and serves as a model system for the investigation of many developmental and cellular processes common to higher eukaryotes, including humans. We have determined the nucleotide sequence of nearly all of the ∼120-megabase euchromatic portion of the Drosophila genome using a whole-genome shotgun sequencing strategy supported by extensive clone-based sequence and a high-quality bacterial artificial chromosome physical map. Efforts are under way to close the remaining gaps; however, the sequence is of sufficient accuracy and contiguity to be declared substantially complete and to support an initial analysis of genome structure and preliminary gene annotation and interpretation. The genome encodes ∼13,600 genes, somewhat fewer than the smaller Caenorhabditis elegans genome, but with comparable functional diversity.

Among the early anatomists, Vesalius (1543) pictured the oesophageal branches of the left gastric vessels lying close to the vagus nerves. According to Bartholin (1673) the veins of the oesophagus drain into the azygos, intercostal, and jugular veins. Dionis (1703) was probably the first to point out that the veins of the oesophagus drain into the left gastric vein. Portal (1803) described oesophageal veins going to the main veins of the neck and thorax, including the bronchial veins, and to the left gastric vein.According to Preble (1900), Fauvel reported the first case of rupture of oesophageal varices in cirrhosis of the liver in 1858. This stimulated a considerable amount of interest in the anastomoses between the portal and systemic veins, and a number of French investigators examined the veins of the oesophagus from this point of view (Kundrat, 1886;Dusaussay, 1877;Duret, 1878;and Mariau, 1893). Their accounts are at variance on many points, particularly with regard to the area of the oesophagus draining into the portal vein. Kundrat regarded the lower onethird of the oesophagus as draining into the portal vein; according to Dusaussay and Mariau the lower two-thirds did so. None of these investigators mentioned valves or discussed the possible effect of pressure differences between the portal and systemic veins. They also disagreed as to the relative size, pattern, and drainage routes of the peri-oesophageal and submucous venous plexuses. Mariau alone mentioned longitudinal veins running with the vagus nerves on the outer surface of the oesophagus.Kegaries (1934) stated that there was no peri-oesophageal plexus but only three to four longitudinal veins on the outer surface of the oesophagus, but he did not mention their relationship to the vagus nerves. Cross anastomoses between these veins were uncommon. The submucosa contained many veins lying both deep and superficial to the muscularis mucosae. Fine longitudinal veins connected the submucous venous plexuses of the stomach and oesophagus. They began at the cardia and ran for 4 to 5 cm. along the oesophagus and were not connected by cross anastomoses. It is not clear from his description whether these veins were deep or superficial to the muscularis mucosae. They drained into the left gas:ric vein by vessels which passed obliquely through the wall of the oesophagus. Th-appearance of some specimens suggested that the fine anastomotic channels in the submucosa may occasionally be absent. The left gastric vein received a peri-oesophageal branch which joined it just below the cardia.Connexions between the pulmonary veins and the veins of the mediastinum, including the veins of the oesophagus, have been described, and the relevant literaon 10 May 2018 by guest. Protected by copyright.

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