One side is one thing
The other is not
This I was born with
It’s what I got….
A chimera is an individual whose body is composed of cells that are genetically distinct, as if they are from different individuals – and sometimes they really are from different individuals.
All animals develop from a single fertilised egg, so in theory every single cell in the body should have exactly the same genome. But chimeras can arise in several ways. The most dramatic is when two embryos that would normally develop into non-identical twins fuse in the womb. Parts of the resulting individual derive from one embryo and parts from another.