Chimaeras

About Chimaeras:

• A genetic chimaera is a single organism composed of cells of more than one distinct genotype (or genetic makeup).
• The animal kingdom has several examples of varying degrees of chimerism.
  • The half-sider budgerigar, a type of common parakeet widely adopted as pets, has different colours on either side of its body due to chimerism.
  • Anglerfish: The male fish fuses with and is eventually absorbed into the female fish, mixing their genetic makeups into a single animal.
  • Marine sponges are known to have up to four distinct genotypes in a single organism.
• Natural chimaeras among humans
  • They occur when the genetic material in one cell changes and gives rise to a clonal population of cells different from all the other cells.
  • The fusion of two fertilised zygotes early in the embryonic stage can also lead to a condition in which two genetic makeups coexist in a single individual.
  • Chimerism can also result from twin or multiple pregnancies evolving into a single foetus or a twin foetus being absorbed into a singleton.