Nucleotide sequences of B1 SINE and 4.5S(I) RNA support a close relationship of zokors to blind mole rats (Spalacinae) and bamboo rats (Rhizomyinae).

Until recently, zokors (Myospalacinae) were assigned to the Cricetidae family. However, analysis of mitochondrial and nuclear genes suggests a sister relationship between zokors and subterranean rodents of the Spalacidae family, namely blind mole rats (Spalacinae) and bamboo rats (Rhizomyinae). Here, we cloned and sequenced copies of the B1 short interspersed element (SINE) from the genome of zokor Myospalax psilurus. The consensus nucleotide sequence of zokor B1 was very similar to spalacids and rhizomyids, but not cricetids. Similar to spalacids (Spalax microphthalmus) and rhizomyids (Tachyoryctes splendens), zokor contained two variants of the 4.5S(I) small nuclear RNA. The longer variant (L-variant, 104 nucleotides) was found only in zokor, spalacids and rhizomyids. The short, or S-variant (98 nucleotides), had a wider distribution; however, analysis of the nucleotide sequences of S-variants of 4.5S(I) RNA confirmed that zokors are closely related to spalacids and rhizomyids, but not to cricetids. The evolution of the 4.5S(I) RNA genes and pseudogenes is discussed.