From this story in Quanta Magazine:
In fact, there’s no single set of genes that all living things need in order to exist. When scientists first began searching for such a thing 20 years ago, they hoped that simply comparing the genome sequences from a bunch of different species would reveal an essential core shared by all species. But as the number of genome sequences blossomed, that essential core disappeared. In 2010, David Ussery, a biologist at Oak Ridge National Laboratory in Tennessee, and his collaborators compared 1,000 genomes. They found that not a single gene is shared across all of life.