Why do plants and animals have to be similar in their genetic makeup to humans?

Question

Why do plants and animals have to be similar in their genetic makeup to humans?

Answer 1

Why do they *have* to be?   No reason.   Plants and humans could just as easily survive using genetic pathways completely unlike each other.

But the fact that they *do* share genetic features ... from the structure of the DNA, to the same 20 amino acids they code for, same codon-to-amino-acid encondings, and many identical metabolic pathways, and letter-for-letter identical segments of DNA ... all are evidence of inheritance from common early one-celled ancestors.

Answer 2

Not sure what you're asking, but the main similarity of plants and animals to humans when it comes to DNA is we all have linear DNA.