March 24 (Reuters) - Revealing the limitations of cloning, researchers who repeatedly cloned mice for two decades have discovered that such serial duplication triggers grave genetic mutations that accumulate over the generations and ultimately become f... March 24 (Reuters) – Revealing the limitations of cloning, researchers who repeatedly cloned mice for two decades have discovered that such serial duplication triggers grave genetic mutations that accumulate over the generations and ultimately become... [4528 chars]