Chimera (noun, “ky-MEER-ah”)
A chimera is an individual organism made of cells from two or more organisms.
The name chimera comes from Greek mythology. In mythology, the Chimera was a creature with a lion’s head, a goat’s body and a snake’s tail. This creature never existed. But organisms with cells — and therefore genes — from two or more organisms do.
Chimeras can form naturally or by artificial means. Natural chimeras can form when separate embryos, or even fertilized eggs, fuse during development. This results in an individual that contains cells from both. Chimeras also occur as a natural part of some species’ life cycle. Some marine sponges are chimeric, as are anglerfish.
Female anglerfish are much larger than males. As adults, males latch their tiny bodies onto a female. Permanently. Over time, the male’s body fuses with the female’s. Most of the male’s organs melt away. Only the male’s reproductive structures — gonads — remain. The female uses them to fertilize her eggs. The female anglerfish’s body now contains both her cells and the male’s. Thus, she is a natural chimera.
Humans can create chimeras artificially, too. For example, grafting is a technique that involves sealing the cut ends of two separate plants together. Once healed, a successfully grafted plant will grow as one plant. That one plant, however, consists of parts from multiple plants. This allows people to grow one plant with characteristics of two. For example, a botanist may graft a tree known for producing delicious fruit to a root known for resisting disease. The result is a tree with both hardy roots and yummy fruit.
The term “chimeric” also comes up in molecular biology. It describes lab-made molecules with pieces of DNA from different sources. Some drugs that treat cancer and other conditions include lab-made chimeric molecules.
In a sentence
Ancient myths about a half-horse, half-human centaur show that chimeras appeared in human imagination long before their scientific discovery.
