Nuclear abnormalities in peripheral blood erythrocytes of penguins "Pygoscelis papua". "A" – "notched" nucleus; "B" – nucleus with altered shape; "C" – "notched" nucleus (upper arrow), nucleus with cavity (lower arrow); "D" – nucleus with cavity. Blood samples were made by Assist. Prof. Dr. Vladimir Bezrukov, Taras Shevchenko National University of Kyiv, in 2003-2004 during VIII Ukrainian Antarctic expedition (Gentoo Penguin Colony, Petermann island, 65°10'S, 64°10'W).