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The Code of Life · Chapter 3

Mistakes and Marvels

Why the copy is never quite perfect — and why that's the point

Mutations are DNA changes that arise without regard to what an organism needs. Their effects depend on context: many have little or no effect, some are harmful, and a few help in particular environments. Passed down, those differences make adaptation possible.

8 panels · ~5 min read

A changed but valid G-C DNA pair, replacing the original A-T pair, is circled by Wren's glowing marker.

Panel 1

Many unchanged dishes, a few spoiled dishes, and one rare variation that proves useful in its particular surroundings.

Panel 2

Ultraviolet radiation and a mutagen damage DNA at separate spots while an unguided copying-and-repair process can preserve a mutation.

Panel 3

A sunny meadow full of the same kind of beetle, each slightly different in color, size, and shine — no two exactly alike.

Panel 4

Two parent beetles with larvae and varied next-generation adults, only some of which share one parent's distinctive bronze-green color.

Panel 5

An adult drinks milk while several branching ancestral populations show distinct inherited paths to lactase persistence.

Panel 6

Identical organisms remain alive and reproduce as their environment changes, but lack heritable variation for genetic adaptation, unlike a varied population nearby.

Panel 7

The varied beetle meadow at golden hour, a bird's shadow falling across the grass unnoticed by the beetles, as the biologist looks up toward the unseen bird.

Panel 8

Cover