Chimerism is a biological condition where an individual has two or more genetically distinct cell lines within their body. This can occur naturally, such as when two embryos fuse in the womb, or artificially, through medical procedures like organ transplants. As a result, a person with chimerism may have different DNA in different tissues, which can lead to unique physical traits or medical implications. In humans, chimerism can sometimes be detected through genetic testing, revealing discrepancies between blood and tissue samples. While it is rare, it has been documented in various species, including mice and plants. Understanding chimerism can provide insights into genetics, development, and even potential medical treatments.