Abstract
The Reverse Transcriptase of the Human Immunodeficiency Virus (HIV) is distinguished by its high rate of homologous recombination. A less-studied consequence of this phenomenon is the increased occurrence of non-homologous recombination, which results in length polymorphism. While most of these genome-wide variations are sporadic, some provide a replication advantage to variant strains, such as those in the Long Terminal Repeat (LTR) and p6-Gag regions. By analyzing sequences from these two regions in the HIV-1 databases, we categorize all types of non-homologous recombination into four groups based on the presence or absence of two molecular features. Additionally, drawing on established models of homologous recombination, we propose a model that describes the process of sequence duplication. This model can also be applied to explain non-homologous recombination in different types of HIV and other viruses.