Look at their "sample selection" section. "The goal of sample selection was to select a set of individuals that collectively captured the maximum amount of weighted allelic diversity53." And also says "We also added the three Ashkenazim Trio samples and the Puerto Rican individual (HG00733). These four samples were added for the purposes of comparison with other studies that are using them."
Four genomes make a comprehensive evaluation set, don't think HG001 is "absolutely" needed.
Four genomes make a comprehensive evaluation set, don't think HG001 is "absolutely" needed.