Haplogroup O-M176

In human population genetics, Y-Chromosome haplogroups define the major lineages of direct paternal (male) lines back to a shared common ancestor in Africa. Haplogroup O-M176 (aka O-SRY465) is a human Y-chromosome DNA haplogroup. It is best known for its part in the settlement of Korea and Japan. It is a descendant of Haplogroup O-P31.

Distribution

Haplogroup O-M176 is found mainly in the northernmost parts of East Asia, from the Uriankhai and Zakhchin peoples of western Mongolia (Katoh 2004) to the Japanese of Japan, though it also has been detected sporadically in the Buryats (Jin 2003) and Udegeys (Jin 2010) of southern Siberia, very rarely among populations of Southeast Asia including Indonesia (Hammer 2006 and Jin 2003), the Philippines (Jin 2003), Thailand (Jin 2003), and Vietnam (Hammer 2006 and Jin 2003), and Micronesians (Hammer 2006). This haplogroup is found with its highest frequency and diversity values among modern populations of Japan and Korea and is absent from most populations in China, but it has been detected in some samples of Han Chinese from Beijing (Jin 2003), Xi'an (1/34, Kim 2011), Jiangsu (Lu 2008), Wuhan (1/160),South China outside of Jiangsu, Anhui, Zhejiang, and Shanghai (1/65), and Taiwan (1/34 Hakka and 1/258 other miscellaneous Han), and Daurs (Xue 2006), Hezhes (Xue 2006), Koreans in China (Xue 2006 and Katoh 2004), Manchus (Xue 2006, Katoh 2004, and Karafet 2001), Sibes (Xue 2006), and Kham Tibetans.

Airco DH.4

The Airco DH.4 was a British two-seat biplane day bomber of World War I. It was designed by Geoffrey de Havilland (hence "DH") for Airco, and was the first British two-seat light day-bomber to have an effective defensive armament. It first flew in August 1916 and entered service with the Royal Flying Corps (RFC) in March 1917. The majority of DH.4s were actually built as general purpose two-seaters in the United States, for service with the American forces in France.

The DH.4 was tried with several engines, of which the best was the 375 hp (280 kW) Rolls-Royce Eagle engine. Armament and ordnance for the aircraft consisted of one 0.303 in (7.7 mm) Vickers machine gun for the pilot and one 0.303 in (7.7 mm) Lewis gun on a Scarff ring mounting for the observer. Two 230 lb (100 kg) bombs or four 112 lb (51 kg) bombs could be carried. The DH.4 entered service on 6 March 1917 with No. 55 Squadron in France.

Design and development

The DH.4 was designed by Geoffrey de Havilland as a light two-seat day bomber powered by the new BHP engine. The prototype first flew in August 1916, powered by a prototype BHP engine rated at 230 hp (170 kW). While the DH.4 trials were promising, the BHP engine required major redesign before entering production, and the Rolls-Royce Eagle engine was selected as the DH.4's powerplant. The first order for 50 DH.4s, powered by 250 hp (186 kW) Eagle III engines was placed at the end of 1916.