Phylogenetic tree of human gamma-satellite repeats SAT, GSATII, and GSATX copies were extracted from the UCSC human genome annotation. From each gamma-satellite array, one monomer was selected and aligned in MAFFT (Katoh et al. 2005). Partial GSAT copies were excluded from the analysis. The tree was obtained using the neighbor-joining method implemented in ClustalW (Chenna et al. 2003) and 1000 bootstrap replicates.