Excess RA at day 8 would most likely afect the CNS PNS advan

Excess RA at day 8 would most likely afect the CNS PNS advanced vertebral paterning retardation of vertebral paterning Which of the following are not organizer molecules in the amphibian? Chordin Otx2 Vg1 VegT Xnr3 Follistatin Noggin Goosecoid Frzb Cerebrus BMP4

Solution

5. Excess RA (retinoic acid) at day 8 affects the central nervous system (CNS). This is because, at day 8 development of central nervous system and organogenesis is initiated and RA levels ar required sufficienty for neural tube formation and neuron differentiation. Excess RA levels may cause degenration or hyperactivity of neurons in CNS resulting in Parkinson\'s disease. Option 1is correct.

6. In amphibians, Sperman\'s organizer is the major part in axis development, neural tube and neural plate formation. The nuclear and secreted proteins act as organizer molecules. These include chordin, Otx2, Follistatin, Noggin, Goosecoid, Frzb,cerebrus . The proteins Vg1, VegT, Xnr3 and BMP4 are not included in proteins of organizer molecules. Options 3, 4, 5 and 11 are correct.