Werner Arber (vĕr´nər är´bər), 1929–, Swiss microbiologist. A professor at the Univ. of Geneva (1960–70) and later at the Univ. of Basel (1971–), Arber worked with Daniel Nathans and Hamilton Othanel Smith to understand the nature of genes. The trio discovered and used certain enzymes that break down genetic material in order to study hereditary mutation in bacteria. For their work the three shared the 1978 Nobel Prize in Physiology or Medicine.