|An ancient coin depicting a chimera|
The modern definition of chimera is also of a combined creature, but of a very different sort. Instead of a combination of different animals, a chimera is basically twins in one body. Twins are conceived, but one dies during development. Instead of the dead twin being lost, the two embryos fuse together, leading to a single embryo with two different sets of genetic material. It is not uncommon for individuals to go their entire lives without being aware of their unique genetics. Many chimeras will have no visible signs of the abnormality. In contrast, however, other chimeras will be visible at birth. Since there are two genotypes involved, it is very possible for a chimera to have two different skin pigments, eye colors, or hair colors present, as seen in the mouse below. If the chimera is produced from opposite-sex twins, it would also be possible for abnormalities to occur in the genitals.
|A chimeric mouse with her offspring.|