The designated "universal genetic code" is the complex information system contained within DNA and is unique to every species and overall similar within all organisms.
There is no remaining DNA from the earliest organisms, but there is every evidence that all organisms that exist or have ever existed utilize DNA as the basis of the universal genetic code that configures life and regulates evolution.
Evolution does not occur without replication and replication does not occur without DNA. The structure of all organisms is protein based, which are virtually all specified by DNA, which itself is made up of proteins. A serious chicken and egg conundrum.
Present hypotheses about the origin of life, OoL, are restricted to purely natural conditions and causes for OoL because of the ideological belief called philosophical naturalism, but tis cannot explain the origin of DNA.
DNA is multi-level organically coded, intelligently designed and irreducibly complex, homochiral structured, most complex information in the universe, bar none. It has no natural process explanation. It is the basis for all evolution and the common design of all organisms.
Current naturalistic propositions about OoL will never find the source of OoL or explain the creation of DNA.