Fig. 7
From: Utilization of HIV-1 envelope V3 to identify X4- and R5-specific Tat and LTR sequence signatures
Statistically divergent Tat positions demonstrate reduced diversity within X4-classified sequences. Within HIV-1 Tat, four amino acid positions were identified as having statistically significant Jensen–Shannon divergence: 7, 23, 57, and 60. In all four cases, it was noted that X4-classified variants exhibited a lower overall genetic diversity at an order of 1, largely due to the enhanced presence of the most common variant in the X4 population. This pattern of diminished diversity within X4 in comparison to R5 suggests that a purifying selective force may be present, affecting a subset of HIV-1 Tat variants