LONDON, Nov 26 (Reuters) - News of a new coronavirus variant potentially resistant to current vaccines sent investors dashing for the safety of the Japanese yen and the Swiss franc on Friday, while the possible unwinding of U.S. rate hike bets weighed on the dollar. The yen and franc gains came at the expense of the growth-sensitive Australian dollar and Norwegian crown though thinner volumes after Thursday"s U.S. Thanksgiving holiday made market moves more volatile. Little is known of the new COVID-19 variant, detected in South Africa, Botswana and Hong Kong. But scientists reckon it has an unusual combination of mutations that may make it able to evade immune responses and be more transmissible. read more The news sent the South African rand down more than 2% against the dollar to the lowest since last November though it later pared those losses. One of the main gainers was the yen which bounced off five-year lows hit this week against the greenback, and jumped more than 1% to a high of 113.6. The currency was on track for its best day since March 2020. The euro, meanwhile rose 0.7% to a high of $1.129 though it fell to near 6-1/2 year lows against the resurgent Swiss franc at 1.044 francs per euro. "This is a textbook flight to quality into yen and the Swiss franc on the new virus strain with the thin liquidity also a factor which may accelerate the unwinding of short bond positions," said Kenneth Broux, a strategist at Societe Generale in London. Speculative accounts had been massively short safe-haven assets, with U.S. CFTC figures showing net bearish positioning at $1.2 billion and $10.3 billion for the yen and Swiss franc respectively in the latest week. Gold, which rose 1% on Friday, had a short position of over $2 billion, the data showed. "It"s not surprising to see the yen being the biggest gainer. First, it"s the quintessential safe-haven and second it was very oversold," said ING Bank currency strategist Francesco Pesole. "Short yen positions are now being unwound." He added the euro, as another low-yielding currency, was less exposed than cyclical peers such as the Australian dollar, while positioning data showed the single currency too had been oversold. Britain cancelled flights to several countries, noting the new variant was considered by scientists to be the most significant one yet found. read more Sterling slipped to a new 2021 low below $1.33 as the jitters prompted some to scale back bets on an interest rate hike in December read more . Oil"s price slide took the Norwegian crown down 1.2% at one point to the lowest since last August. Against the euro it fell more than 1% . Gains for the yen, franc and euro pushed the dollar index <=USD>, which measures the greenback against those and three other currencies - further away from Wednesday"s 96.938, its highest in nearly 17 months. It last traded at 96.28, down 0.5%. "One potential threat is that hawkish central banks think this variant threatens (policy) tightening plans. From that perspective the dollar may be a bit more vulnerable than the euro as we are already talking of Fed rate hikes next year," Pesole added. Markets had priced in one rate hike from the European Central Bank at the end of 2022 but expectations had built for three possible increases from the Federal Reserve next year. Broux of Societe Generale noted that the spread between the U.S. and German five-year yields had snapped in 10 basis points as Treasury yields fell heavily, allowing the euro to gain against the greenback.