Even so, it’s a big underestimate of what would it would take engineer a mammoth from an elephant genome. Those 2020 substitutions don’t include any cis-regulatory changes, the non-coding sequence changes that affect how and where genes are expressed — there may be even more of those than protein-coding substitutions. Geneticists also will have to figure out which Asian elephant-specific evolutionary changes need reversing to approximate the mammoth-Asian elephant common ancestor. And they must determine to what extent gene duplications or structural changes to the genome might influence mammoth biology.
Obviously, journalists who actually dug into these numbers would have to cover this story very differently. Who would click on a story with an accurate headline? “Forty-five mammoth genes in elephant cells, more than 4000 to go!” But by accurately telling the numbers, they would emphasize the difference between resurrecting an extinct species and slightly modifying a living one.