Answer Happy

Two parents present to you, a genetic counsellor. The mother hasrecently been diagnosed with retinoblastoma, an autosomal dominantdisorder that affects vision. She subsequently underwent genetictesting and was deemed heterozygous for the Rb gene. The father hasa “normal” phenotype (i.e., he does not have retinoblastoma)
Unfortunately, a mutation in a signaling pathway occurred thatprevents development of the presumptive vertebral column. Predictduring what step in embryonic development this could have occurredand what structure could have failed to form. What subsequentstructure will not form because of the loss of this firststructure? Explain