Parasite Eve

When Dr. Nagashima loses his wife in a mysterious car crash, he is overwhelmed with grief but also an eerie sense of purpose; he becomes obsessed with reincarnating his dead wife. Her donated kidney is transplanted into a young girl with a debilitating disorder, but the doctor also feels compelled to keep a small sample of her liver in his laboratory. When these cells start mutating rapidly, a consciousness bent on determining its own fate awakens, bent on becoming the new dominant species on earth.