Replication of myxoma and vaccinia viruses in cells from most mammalian species is aborted by “intrinsic” host cell restriction genes, SAMD9 and SAMD9L, against which both viruses have evolved unique evasion proteins that bind with high affinity to the SAMD9/SAMD9L proteins and block their antiviral effect.81, 82, 83, 84. The gene discussed is SAMD9L; the disease is myxoma.