instruction:
Given a context passage, generate a question from the passage such that its answer is shortest continous span from the passage.
question:
Diamond-Blackfan anemia (DBA) is a congenital bone marrow failure syndrome characterized by hypoproliferative anemia, associated physical malformations and a predisposition to cancer. DBA has been associated with mutations and deletions in the large and small ribosomal protein genes, and genetic aberrations have been detected in 50-60% of patients. In this study, nine Korean DBA patients were screened for mutations in eight known DBA genes (RPS19, RPS24, RPS17, RPS10, RPS26, RPL35A, RPL5 and RPL11) using the direct sequencing method. Mutations in RPS19, RPS26 and RPS17 were detected in four, two and one patient, respectively. Among the mutations detected in RPS19, two mutations were novel (c.26T>A, c.357-2A>G). For the mutation-negative cases, array-CGH analysis was performed to identify copy-number variations, and no deletions involving the known DBA gene regions were identified. The relative mRNA expression of RPS19 estimated using real-time quantitative PCR analysis revealed two- to fourfold reductions in RPS19 mRNA expression in three patients with RPS19 mutations, and p53 protein expression analysis by immunohistochemistry showed variable but significant nuclear staining in the DBA patients. In conclusion, heterozygous mutations in the known DBA genes RPS19, RPS26 and RPS17 were detected in seven out of nine Korean DBA patients. Among these patients, RPS19 was the most frequently mutated gene. In addition, decreased RPS19 mRNA expression and p53 overexpression were observed in the Korean DBA patients, which supports the hypothesis that haploinsufficiency and p53 hyperactivation represent a central pathway underlying the pathogenesis of DBA.
answer:
In which syndrome is the RPS19 gene most frequently mutated?

question:
Alfred Wegener, born in 1880, was a meteorologist and explorer. In 1911, Wegener found a scientific paper that listed identical plant and animal fossils on opposite sides of the Atlantic Ocean. Intrigued, he then searched for and found other cases of identical fossils on opposite sides of oceans. The explanation put out by the scientists of the day was that land bridges had once stretched between these continents. Instead, Wegener pondered the way Africa and South America appeared to fit together like puzzle pieces. Other scientists had suggested that Africa and South America had once been joined, but Wegener was the ideas most dogged supporter. Wegener amassed a tremendous amount of evidence to support his hypothesis that the continents had once been joined. Imagine that youre Wegeners colleague. What sort of evidence would you look for to see if the continents had actually been joined and had moved apart? Here is the main evidence that Wegener and his supporters collected for the continental drift hypothesis: The continents appear to fit together. Ancient fossils of the same species of extinct plants and animals are found in rocks of the same age but are on continents that are now widely separated (Figure 1.1). Wegener proposed that the organisms had lived side by side, but that the lands had moved apart after they were dead and fossilized. His critics suggested that the organisms moved over long-gone land bridges, but Wegener thought that the organisms could not have been able to travel across the oceans. Fossils of the seed fern Glossopteris were too heavy to be carried so far by wind. Mesosaurus was a swimming reptile, but could only swim in fresh water. Cynognathus and Lystrosaurus were land reptiles and were unable to swim. Wegener used fossil evidence to support his continental drift hypothesis. The fos- sils of these organisms are found on lands that are now far apart. Identical rocks, of the same type and age, are found on both sides of the Atlantic Ocean. Wegener said the rocks had formed side by side and that the land had since moved apart. Mountain ranges with the same rock types, structures, and ages are now on opposite sides of the Atlantic Ocean. The Appalachians of the eastern United States and Canada, for example, are just like mountain ranges in eastern Greenland, Ireland, Great Britain, and Norway (Figure 1.2). Wegener concluded that they formed as a single mountain range that was separated as the continents drifted. Grooves and rock deposits left by ancient glaciers are found today on different continents very close to the Equator. This would indicate that the glaciers either formed in the middle of the ocean and/or covered most of the Earth. Today, glaciers only form on land and nearer the poles. Wegener thought that the glaciers were centered over the southern land mass close to the South Pole and the continents moved to their present positions later on. The similarities between the Appalachian and the eastern Greenland mountain ranges are evidences for the continental drift hypothesis. Coral reefs and coal-forming swamps are found in tropical and subtropical environments, but ancient coal seams and coral reefs are found in locations where it is much too cold today. Wegener suggested that these creatures were alive in warm climate zones and that the fossils and coal later drifted to new locations on the continents. Wegener thought that mountains formed as continents ran into each other. This got around the problem of the leading hypothesis of the day, which was that Earth had been a molten ball that bulked up in spots as it cooled (the problem with this idea was that the mountains should all be the same age and they were known not to be). Click image to the left or use the URL below. URL:
answer:
the coast of south america fits closely to this continent like a puzzle piece.

question:
Thermohaline circulation drives deep ocean circulation. Thermo means heat and haline refers to salinity. Dif- ferences in temperature and in salinity change the density of seawater. So thermohaline circulation is the result of density differences in water masses because of their different temperature and salinity. What is the temperature and salinity of very dense water? Lower temperature and higher salinity yield the densest water. When a volume of water is cooled, the molecules move less vigorously, so same number of molecules takes up less space and the water is denser. If salt is added to a volume of water, there are more molecules in the same volume, so the water is denser. Changes in temperature and salinity of seawater take place at the surface. Water becomes dense near the poles. Cold polar air cools the water and lowers its temperature, increasing its salinity. Fresh water freezes out of seawater to become sea ice, which also increases the salinity of the remaining water. This very cold, very saline water is very dense and sinks. This sinking is called downwelling. This video lecture discusses the vertical distribution of life in the oceans. Seawater density creates currents, which provide different habitats for different creatures: Click image to the left or use the URL below. URL: Two things then happen. The dense water pushes deeper water out of its way and that water moves along the bottom of the ocean. This deep water mixes with less dense water as it flows. Surface currents move water into the space vacated at the surface where the dense water sank (Figure 1.1). Water also sinks into the deep ocean off of Antarctica. Cold water (blue lines) sinks in the North Atlantic, flows along the bottom of the ocean and upwells in the Pacific or Indian. The water then travels in surface currents (red lines) back to the North Atlantic. Deep water also forms off of Antarctica. Since unlimited amounts of water cannot sink to the bottom of the ocean, water must rise from the deep ocean to the surface somewhere. This process is called upwelling (Figure 1.2). Upwelling forces denser water from below to take the place of less dense water at the surface that is pushed away by the wind. Generally, upwelling occurs along the coast when wind blows water strongly away from the shore. This leaves a void that is filled by deep water that rises to the surface. Upwelling is extremely important where it occurs. During its time on the bottom, the cold deep water has collected nutrients that have fallen down through the water column. Upwelling brings those nutrients to the surface. Those nutrients support the growth of plankton and form the base of a rich ecosystem. California, South America, South Africa, and the Arabian Sea all benefit from offshore upwelling. Upwelling also takes place along the Equator between the North and South Equatorial Currents. Winds blow the surface water north and south of the Equator, so deep water undergoes upwelling. The nutrients rise to the surface and support a great deal of life in the equatorial oceans. Click image to the left or use the URL below. URL:
answer:
what helps to bring cool, nutrient-rich water to the surface?