Practice question

Totipotency denotes maximal developmental potential to generate organism in entirety including embryonic lineages forming all fetal tissues plus extraembryonic tissues such as trophectoderm forming placenta and primitive endoderm forming yolk sac membranes. In mammals zygote and early blastomeres up to 2-cell stage retain totipotency as demonstrated by blastomere isolation producing viable twins and tetraploid complementation. Pluripotency limited to embryonic tissues excluding trophectoderm seen in inner cell mass embryonic stem cells forming teratoma. Unipotent limited to single lineage like epidermis, unlimited symmetric division describes self-renewal mode not potency spectrum. Totipotency represents foundation of embryonic development and cloning.