Which term describes an organism composed of cells from two different zygotes?

Which term describes an organism composed of cells from two different zygotes?

• A. Chimera
• B. Homozygous
• C. Transgenic
• D. Knockout

Answer: (A)

Chimera describes an organism that carries two genetically distinct cell populations derived from two different zygotes. This can happen if two embryos fuse early in development or if cells from one embryo are introduced into another’s blastocyst, resulting in tissues that come from both zygotes. Because the cell lines have separate genetic origins, different tissues can have different genotypes, and sometimes both lineages contribute to the germline. This differs from being homozygous, where every cell has the same alleles; transgenic, where foreign DNA is added into the genome; and a knockout, where a specific gene is inactivated. So, the organism composed of cells from two zygotes is a chimera.

Chimera describes an organism that carries two genetically distinct cell populations derived from two different zygotes. This can happen if two embryos fuse early in development or if cells from one embryo are introduced into another’s blastocyst, resulting in tissues that come from both zygotes. Because the cell lines have separate genetic origins, different tissues can have different genotypes, and sometimes both lineages contribute to the germline. This differs from being homozygous, where every cell has the same alleles; transgenic, where foreign DNA is added into the genome; and a knockout, where a specific gene is inactivated. So, the organism composed of cells from two zygotes is a chimera.