Djibouti City (pop., 1995 est.: 383,000), major port, and capital of Dji¬ bouti. Located on the southern shore of the Gulf of Tadjoura in the Gulf of Aden, it was founded by the French in 1888 and made the capital of French Somaliland in 1892. Linked by rail to Addis Ababa in 1917, it was made a free port in 1949. The economic life of both the city and the nation depends on the city’s function as a transshipment point, especially between Ethiopia and the Red Sea trade. Built on three level areas linked by jetties, the city has a mixture of ancient and modem architecture. Drought and war during the 1980s and early ’90s brought many refugees to Djibouti from Somalia and Ethiopia, swelling its population.
Djilas Vji-las\, Milovan (b. June 12, 1911, Podbisce, Montenegro—d. April 20, 1995, Belgrade, Serbia) Yugoslav politician and political writer. His opposition to Yugoslavia’s royalist dictatorship led to a prison term (1933-36). He joined the Yugoslav Communist Party’s central commit}tee in 1938 and its politburo in 1940. In World War II he played a major role in the partisan resistance to the Germans. In 1953 he became president of the Federal People’s Assembly, but his criticism of the party and calls for liberalization soon led to his ouster from all political posts by Tito. He was later arrested several times after his books criticizing communism, including The New Class (1957), were published in the West.
Dmitry, False or Pseudo-Demetrius Any of three pretenders to the Muscovite throne who, during the Time of Troubles, claimed to be Ivan IV’s child Dmitry Ivanovich, who had died mysteriously while still a child, possibly murdered at the order of Boris Godunov. The first False Dmitry challenged Godunov’s right to the throne and was proclaimed tsar in 1605. In 1606 he was murdered by Vasily Shuysky (1552-1612), who succeeded him. Rumors spread that Dmitry had survived, and a sec¬ ond pretender gained a large following before being killed in 1610. A third False Dmitry appeared in 1611, gaining the allegiance of the Cos¬ sacks and the inhabitants of Pskov, but he was executed in 1612.
DNA or deoxyribonucleic Xde-'ak-si-.ri-bo-nyu-'kle-ik, de-'ak- si-.ri-bo-nyu-'kla-ikA acid One of two types of nucleic acid (the other is RNA); a complex organic compound found in all living cells and many viRUSes. It is the chemical substance of genes. Its structure, with two strands wound around each other in a double helix to resemble a twisted ladder, was first described (1953) by Francis Crick and James D. Watson. Each strand is a long chain (polymer) of repeating nucleotides: adenine (A), guanine (G), cytosine (C), and thymine (T). The two strands contain complementary information: A forms hydrogen bonds (see hydrogen bonding) only with T, C only with G. When DNA is copied in the cell, the strands separate and each serves as a template for assembling a new complementary strand; this is the key to stable heredity. DNA in cells is organized into dense protein-DNA complexes (see nucleoprotein) called chromosomes. In eukaryotes these are in the nucleus, and DNA also occurs in mitochondria and chloroplasts (if any). Prokaryotes have a single cir¬ cular chromosome in the cytoplasm. Some prokaryotes and a few eukary¬ otes have DNA outside the chromosomes in plasmids. See also Rosalind Franklin; genetic engineering; mutation; Maurice Wilkins. See illustration on following page.
DNA computing Form of computing in which DNA molecules are used instead of digital logic circuits. The biological cell is regarded as an entity that resembles a sophisticated computer. The four amino acid bases that are constituents of DNA, traditionally represented by the letters A, T, C, and G, are used as operators, as the binary digits 0 and 1 are used in computers. DNA molecules are encoded to a researcher’s specifications and then induced to recombine (see recombination), resulting in trillions of
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556 I DNA fingerprinting ► Doctorow
A. B.
1 2 ^ 3 4 5
DNA double helix. A. Molecular model of DNA. The molecules include (1) hydro¬ gen, (2) oxygen (3) carbon and nitrogen in the linked nitrogenous bases, (4) car¬ bon in the sugar deoxyribose, and (5) phosphorus. B. Schematic representation of DNA. The twisted ladder shape consists of (6) nitrogenous base pairs joined by hydrogen bonds, on (7) a sugar-phosphate backbone.
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“calculations” simultaneously. The field is in its infancy and its implica¬ tions are only beginning to be explored. See also quantum computing.
DNA fingerprinting Method developed by the British geneticist Alec Jeffreys (born 1950) in 1984 for isolating and making images of sequences of DNA. The procedure consists of obtaining a sample of cells contain¬ ing DNA (e.g., from skin, blood, or hair), extracting the DNA, and puri¬ fying it. The DNA is then cut by enzymes, and the resulting fragments of varying lengths undergo procedures that permit them to be analyzed. The pattern of fragments is unique for each individual. DNA fingerprinting is used to help solve crimes and determine paternity; it is also used to locate gene segments that cause genetic diseases, to map the genetic material of humans (see Human Genome Project), to engineer drought-resistant plants (see genetic engineering), and to produce biological drugs from genetically altered cells.
Dnieper River \'ne-por\ Russian Dnepr Xdo-'nyeprA ancient Borys- thenes. River, eastern central Europe. One of the longest rivers in Europe, it rises west of Moscow and flows south through Belarus and Ukraine, emptying into the Black Sea after a course of 1,420 mi (2,285 km). More than 300 hydroelectric plants operate in the Dnieper basin, and it has several huge dams. Navigable for about 1,042 mi (1,677 km) during the 10 months of the year when it is not frozen, it is an important shipping artery for eastern Europe.
Dniester River \'ne-stor\ Russian Dnestr \do-'nyestr 3 \ ancient Tyras. River, southern central Europe. Rising on the northern side of the Carpathian Mtns., it flows south and east for 840 mi (1,352 km) to the Black Sea near Odessa. It is the second-longest river in Ukraine and the main water artery of Moldova. It is navigable for 750 mi (1,200 km).
Dnipropetrovsk \d9-,nye-pr9-pe-'tr6fsk\ formerly (1783-1926) Eka- terinoslav \i- l ka-ti-'re-no- l slaf\ City (pop., 2001: 3,567,600), south- central Ukraine. Located on the Dnieper River, it was founded in 1783 and named for Catherine the Great; it grew after the railroad arrived in the 1880s. In 1926 the Soviets gave it its current name. A railway junction
and a centre of the wheat trade, it has developed into one of the largest industrial cities of Ukraine, with a huge iron and steel industry. It is the site of institutes of higher education, and its cultural amenities include several theatres.
Doberman pinscher Vdo-bar-mon-'pin-choiA Breed of working dog developed in Apolda, Germany, by Louis Dobermann, a dog-pound keeper, in the late 19th century. This sleek, agile, powerful dog stands 24-28 in. (61-71 cm) high and weighs 60-88 lbs (27^10 kg). It has a short, smooth black, blue, fawn, or red coat, with rust markings on the head, throat, chest, tail base, and feet. Dobermans have a reputation for fearlessness, alertness, loyalty, and intelligence. They have been used in police and military work, as watchdogs, and as guide dogs for the blind.
Doblin Vdoe-.blenV Alfred (b. Aug. 10, 1878, Stettin, Ger.—d. June 26, 1957, Emmendingen, near Freiburg im Breisgau, W.Ger.) German novelist and essayist. He studied medicine at the Universities of Berlin and Freiburg, specializing in psychiatry. His first novel. The Three Leaps of Wang-Lun (1915), describes the quashing of a rebellion in China. His best-known work, Berlin Alexanderplatz (1929; film, 1931; adapted for television, 1980), is written in an Expressionist vein and dramatizes the miseries of working-class life in a disintegrating social order. His Jewish ancestry and socialist views compelled him to leave Germany upon the Nazi takeover, and he fled to France (1933) and then to the U.S. (1940), resettling in Paris in the early 1950s.