This is your morning Open Thread. Pour your favorite beverage and review the past and comment on the future.
Find the past “On This Day in History” here.
February 28 is the 59th day of the year in the Gregorian calendar. There are 306 days remaining until the end of the year (307 in leap years)
On this day in 1953, Cambridge University scientists James D. Watson and Frances H.C. Crick announce that they have determined the double-helix structure of DNA, the molecule containing human genes.
DNA was first isolated by the Swiss physician Friedrich Miescher who, in 1869, discovered a microscopic substance in the pus of discarded surgical bandages. As it resided in the nuclei of cells, he called it “nuclein”. In 1919, Phoebus Levene identified the base, sugar and phosphate nucleotide unit. Levene suggested that DNA consisted of a string of nucleotide units linked together through the phosphate groups. However, Levene thought the chain was short and the bases repeated in a fixed order. In 1937 William Astbury produced the first X-ray diffraction patterns that showed that DNA had a regular structure.
In 1928, Frederick Griffith discovered that traits of the “smooth” form of the Pneumococcus could be transferred to the “rough” form of the same bacteria by mixing killed “smooth” bacteria with the live “rough” form. This system provided the first clear suggestion that DNA carries genetic information, the Avery-MacLeod-McCarty experiment, when Oswald Avery, along with coworkers Colin MacLeod and Maclyn McCarty, identified DNA as the transforming principle in 1943. DNA’s role in heredity was confirmed in 1952, when Alfred Hershey and Martha Chase in the Hershey-Chase experiment showed that DNA is the genetic material of the T2 phage.
In 1953, James D. Watson and Francis Crick suggested what is now accepted as the first correct double-helix model of DNA structure in the journal Nature. Their double-helix, molecular model of DNA was then based on a single X-ray diffraction image (labeled as “Photo 51”) taken by Rosalind Franklin and Raymond Gosling in May 1952, as well as the information that the DNA bases are paired – also obtained through private communications from Erwin Chargaff in the previous years. Chargaff’s rules played a very important role in establishing double-helix configurations for B-DNA as well as A-DNA.
Experimental evidence supporting the Watson and Crick model were published in a series of five articles in the same issue of Nature. Of these, Franklin and Gosling’s paper was the first publication of their own X-ray diffraction data and original analysis method that partially supported the Watson and Crick model; this issue also contained an article on DNA structure by Maurice Wilkins and two of his colleagues, whose analysis and in vivo B-DNA X-ray patterns also supported the presence in vivo of the double-helical DNA configurations as proposed by Crick and Watson for their double-helix molecular model of DNA in the previous two pages of Nature. In 1962, after Franklin’s death, Watson, Crick, and Wilkins jointly received the Nobel Prize in Physiology or Medicine. However, Nobel rules of the time allowed only living recipients, but a vigorous debate continues on who should receive credit for the discovery.
202 BC – coronation ceremony of Liu Bang as Emperor Gaozu of Han takes place, initiating four centuries of the Han Dynasty’s rule over China
1710 – In the Battle of Helsingborg, 14,000 Danish invaders under Jorgen Rantzau are decisively defeated by an equally sized Swedish force under Magnus Stenbock.
1784 – John Wesley charters the Methodist Church.
1827 – The Baltimore & Ohio Railroad is incorporated, becoming the first railroad in America offering commercial transportation of both people and freight.
1838 – Robert Nelson, leader of the Patriotes, proclaims the independence of Lower Canada (today Quebec)
1844 – A gun on USS Princeton explodes while the boat is on a Potomac River cruise, killing eight people, including two United States Cabinet members.
1849 – Regular steamboat service from the west to the east coast of the United States begins with the arrival of the SS California in San Francisco Bay, 4 months 22 days after leaving New York Harbor.
1854 – The Republican Party of the United States is organized in Ripon, Wisconsin.
1870 – The Bulgarian Exarchate is established by decree of Sultan Abd-ul-Aziz of the Ottoman Empire.
1883 – The first vaudeville theater opens in Boston, Massachusetts.
1885 – The American Telephone and Telegraph Company is incorporated in New York State as the subsidiary of American Bell Telephone. (American Bell would later merge with its subsidiary.)
1893 – The USS Indiana, the lead ship of her class and the first battleship in the United States Navy comparable to foreign battleships of the time, is launched.
1900 – The Second Boer War: The 118-day “Siege of Ladysmith” is lifted.
1914 – The Autonomous Republic of Northern Epirus is proclaimed in Gjirokaster, by the Greeks living in southern Albania.
1922 – The United Kingdom ends its protectorate over Egypt through a Unilateral Declaration of Independence.
1933 – Gleichschaltung: The Reichstag Fire Decree is passed in Germany a day after the Reichstag fire.
1935 – DuPont scientist Wallace Carothers invents Nylon.
1939 – The erroneous word “dord” is discovered in the Webster’s New International Dictionary, Second Edition, prompting an investigation.
1940 – Basketball is televised for the first time (Fordham University vs. the University of Pittsburgh in Madison Square Garden).
1942 – The heavy cruiser USS Houston (CA-30) is sunk in the Battle of Sunda Strait with 693 crew members killed, along with HMAS Perth (D29) which lost 375 men.
1947 – 228 Incident: In Taiwan, civil disorder is put down with the loss of 30,000 civilian lives.
1953 – James D. Watson and Francis Crick announce to friends that they have determined the chemical structure of DNA; the formal announcement takes place on April 25 following publication in April Nature (pub. April 2).
1954 – The first-ever color television sets using the NTSC standard are offered for sale to the general public.
1958 – A school bus in Floyd County, Kentucky hits a wrecker truck and plunges down an embankment into the rain-swollen Levisa Fork River. The driver and 26 children die in what remains the worst school bus accident in U.S. history.
1959 – Discoverer 1, an American spy satellite that is the first object to achieve a polar orbit, is launched.
1972 – Sino-American relations: The United States and People’s Republic of China sign the Shanghai Communique.
1980 – Andalusia approves its statute of autonomy through a referendum.
1985 – The Provisional Irish Republican Army carries out a mortar attack on the Royal Ulster Constabulary police station at Newry, killing nine officers in the highest loss of life for the RUC on a single day.
1986 – Olof Palme, Prime Minister of Sweden, is assassinated in Stockholm.
1991 – The first Gulf War ends.
1993 – Bureau of Alcohol, Tobacco and Firearms agents raid the Branch Davidian church in Waco, Texas with a warrant to arrest the group’s leader David Koresh. Four BATF agents and five Davidians die in the initial raid, starting a 51-day standoff.
1997 – An earthquake of magnitude 6.1 in Armenia and Azerbaijan kills around 1,100 people
* 1997 – An earthquake in northern Iran is responsible for about 3,000 deaths.
1997 – The North Hollywood shootout takes place, resulting in the injury of 19 people and the deaths of both perpetrators.
1997 – The leadership of the Turkish Armed Forces issue a memorandum which would lead to the resignation of Prime Minister Necmettin Erbakan and the end of his coalition government.
1997 – GRB 970228, a highly luminous flash of gamma rays, strikes the Earth for 80 seconds, providing early evidence that gamma-ray bursts occur well beyond the Milky Way.
1998 – First flight of RQ-4 Global Hawk, the first unmanned aerial vehicle certified to file its own flight plans and fly regularly in U.S. civilian airspace.
1998 – Kosovo War: Serbian police begin the offensive against the Kosovo Liberation Army in Kosovo.
2001 – The Nisqually Earthquake measuring 6.8 on the Richter Scale hits the Nisqually Valley and the Seattle, Tacoma, and Olympia area of the U.S. state of Washington.
2001 – Six passengers and four railway staff are killed and a further 82 people suffer serious injuries in the Selby rail crash.
2004 – Over 1 million Taiwanese participating in the 228 Hand-in-Hand Rally form a 500-kilometre (300-mile) long human chain to commemorate the 228 Incident in 1947
2005 – Lebanon’s pro-Syrian prime minister, Omar Karami, resigns amid large anti-Syria street demonstrations in Beirut.
2005 – A suicide bombing at a police recruiting centre in Al Hillah, Iraq kills 127.
2007 – Jupiter flyby of the New Horizons Pluto-observer spacecraft.
* Christian Feast Day:
o Hilarius
o Mar Abba
o Rufinus
o February 28 (Eastern Orthodox liturgics)
* Kalevala Day, the day of Finnish Culture. (Finland)
* National Science Day (India)
* Peace Memorial Day (Taiwan)
* Teacher’s Day (Arab countries)
* The third day of Ayyam-i-Ha (Baha’i Faith)
2 comments
a DNA model for science fair project in 9th grade using styrofoam balls, straws & coffee stir sticks. i won second place.
i’ve always thought a spinning DNA (like your graphic) looks like a twirling ballerina… and maybe thats why people love twirling dances so, it’s an imitation of an earthy constant…. (much like the sound of waves echo a beating heart)