A New Family of Retroviral Long Terminal Repeat Elements in the Human Genome Identified by Their Homologies to an Element 5′ to the Spider Monkey Haptoglobin Gene

A new family of retroviral long terminal repeats that we name Spm-LTR has been identified as a result of DNA sequence comparisons between the entire GenBank databank and an element, SPHP, located 5′ to the haptoglobin gene of spider monkeys. The 18 human Spm-LTR sequences so identified fall into three subtypes. There is no sequence similarity between Spm-LTR elements and any endogenous retroviral LTR sequences previously reported except for general features that define LTRs. However, a previously described repeated sequence (MER-4) forms a portion of the Spm-LTR sequence.