Fig. 1.

AGM SAMHD1 is polymorphic. The seven identified SAMHD1 haplotypes (blue triangle) differ at six amino acid positions across the gene. No other nonsynonymous changes were found in any of the individuals outside of these sites, and only six of the 100 sequenced genes contain a synonymous SNP. Ancestral amino acids (white boxes) were inferred by maximum likelihood sequence reconstruction using Ancestral Sequence Reconstruction programs in Datamonkey (32, 33). Purple boxes denote derived amino acid changes. For comparison, the amino acid present in Old World monkey SAMHD1 sequences is shown for each location of AGM SAMHD1 variation. The sources of these sequences were previously reported (16, 17). The relationships of species according to Perelman et al. are shown by cladogram (24).