What is chimerism in genetics?

Published by Anaya Cole on

What is chimerism in genetics?

chimera, in genetics, an organism or tissue that contains at least two different sets of DNA, most often originating from the fusion of as many different zygotes (fertilized eggs). The term is derived from the Chimera of Greek mythology, a fire-breathing monster that was part lion, part goat, and part dragon.

Is chimerism a mutation?

Animal chimeras are produced by the merger of two (or more) embryos. In plant chimeras, however, the distinct types of tissue may originate from the same zygote, and the difference is often due to mutation during ordinary cell division.

Is chimerism a genetic disorder?

When Taylor Muhl was born, her mother was told that her baby’s two-toned skin was a birthmark. Now at 33 years old, Muhl, a musician and model, understands her two-toned skin is actually a result of a genetic condition called chimerism, which causes an individual to have two genomes, or sets of DNA.

What causes genetic chimerism?

In humans, chimerism most commonly occurs when a pregnant woman absorbs a few cells from her fetus. The opposite may also happen, where a fetus absorbs a few cells from its mother. These cells may travel into the mother’s or fetus’s bloodstream and migrate to different organs.

Can identical twins form a chimera?

Chimerism occurs when fraternal twins fuse in the womb. “If identical twins fuse, it’s not a chimera because they have the same genome,” Pappas said. When the two sperm fertilize the two eggs, it results in two single-cell organisms (zygotes), which then divide and grow into embryos.

What is genetic chimerism in biology?

A genetic chimerism or chimera ( /kaɪˈmɪərə/ ky-MEER-ə or /kɪˈmɪərə/ kə-MEER-ə) is a single organism composed of cells with more than one distinct genotype.

What is an example of germline chimerism?

Germline chimerism occurs when the germ cells (for example, sperm and egg cells) of an organism are not genetically identical to its own. It has been recently discovered that marmosets can carry the reproductive cells of their (fraternal) twin siblings due to placental fusion during development.

What is the origin of genetic chimera?

The term genetic chimera has been used at least since the 1944 article of Belgovskii. An animal chimera is a single organism that is composed of two or more different populations of genetically distinct cells that originated from different zygotes involved in sexual reproduction.

What are the phenotypes of chimeras?

Most chimeras will go through life without realizing they are chimeras. The difference in phenotypes may be subtle ( e.g., having a hitchhiker’s thumb and a straight thumb, eyes of slightly different colors, differential hair growth on opposite sides of the body, etc.) or completely undetectable.

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