What term means the presence in one individual of two or more cell lines derived from different individuals?

What term means the presence in one individual of two or more cell lines derived from different individuals?

• A. Chimerism
• B. Blastomere symmetry
• C. Cleavage stage embryos
• D. Biochemical pregnancy

Answer: (A)

Two or more genetically distinct cell lines in one person is called chimerism. This occurs when two fertilized eggs fuse early in development, creating an individual with tissues derived from different genetic origins, or when donor cells from a transplant persist and contribute to the body. The key idea is the presence of mixed genetic lineages from different individuals, which is what makes chimerism the correct term. The other options don’t describe this situation: blastomere symmetry concerns how cells divide in the very early embryo, cleavage stage embryos refer to a developmental stage, and a biochemical pregnancy describes a positive pregnancy test without a viable pregnancy, not mixed cell lines.

Two or more genetically distinct cell lines in one person is called chimerism. This occurs when two fertilized eggs fuse early in development, creating an individual with tissues derived from different genetic origins, or when donor cells from a transplant persist and contribute to the body. The key idea is the presence of mixed genetic lineages from different individuals, which is what makes chimerism the correct term. The other options don’t describe this situation: blastomere symmetry concerns how cells divide in the very early embryo, cleavage stage embryos refer to a developmental stage, and a biochemical pregnancy describes a positive pregnancy test without a viable pregnancy, not mixed cell lines.