The two genes are usually located close to each other(less than 15,000 bases apart) on the same chromosome,
and are transcribed in opposite directions however, in Fugu, the homologs are further apart and transcribed in the same direction.
Alkaloids Ciguatera poisoning Grayanotoxin(honey intoxication) Mushroom toxins Phytohaemagglutinin(red kidney bean poisoning; destroyed by boiling) Pyrrolizidine alkaloids Shellfish toxin, including paralytic shellfish poisoning, diarrhetic shellfish poisoning, neurotoxic shellfish poisoning,
amnesic shellfish poisoning and ciguatera fish poisoning Scombrotoxin Tetrodotoxin(Fugu fish poisoning)
Some plants contain substances which are toxic in large doses, but have therapeutic properties in appropriate dosages.