Evolving Codes and Novel Genes

The genetic code, the translation between each sequence of three nucleotides to an amino acid, is shared widely across the tree of life. Explore Evolution seizes upon some small variations in that translation to claim that common ancestry must be wrong.

Contrary to claims in Explore Evolution, the genetic code is still considered to be universal, in that the known exceptions are very minor variations on the same basic code found in all organisms. Long before the discovery of variant codes, it was known that the genetic code can in fact change, and how it can change, based on laboratory findings in bacteria and yeast mutants. We also have a good understanding of the kind of mutations and selective forces that can allow the genetic code to evolve new variants.

We also have a growing understanding of so-called ORFans, coding DNA sequences which don't seem homologous to genes in any other lineage. In the account of Explore Evolution, these are insuperable challenges to evolution, but this misrepresents the current state of knowledge. The more of these apparently unique sections of coding DNA we study, and the more genomes we sequence, the fewer of these ORFans actually seem unique. Many of what were thought to be ORFans actually have families, and Explore Evolution misinforms students by treating these sequences as unsolvable problems.

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