"A birds egg contains nothing but liquid, yet by itself this develops into a beak, two eyes, and all the other parts which forma bird, and can fly into the sky". (MW vol , Letter to Nikke pg 259-260)
This happens by the processes of meiosis and mitosis. A Buddha is born through the process of following what the Buddha and Nichiren Daishonin taught.
A human being contains 46 chromosomes in every one of it's cells except in the sex cells which contain 23. When a sperm fertilizes an egg the 23 chromosomes from the male unite with the 23 chromosomes from the female to form 46 chromosomes. These 46 chromosome control the eventual shape structure, and function of the human body. Normal chromosomes will beget a normal body "mind".
There are certain anomalous processes that occur within chromosomes. They are called deletions, translocations, inversions, additions and mutations. There are control mechanisms that help to prevent these processes from occurring and there are repair mechanisms that can reverse some of these abnormal processes after they occur.
The Lotus Sutra and Gosho (Law) and The Buddha unite with the faith and practice of the believer to control the "shape, structure, and function" of the believer's Buddhahood. These can be likened to chromosomes of faith.
Normal chromosomes can be likened to the correct Law, the correct Buddha, a correct faith, and a correct practice. All these normal or correct conditions must be present in order to attain Buddhahood in this lifetime. Abnormal chromosomes can be likened to an incorrect Law, any Buddha (or person) besides the Original Buddha, an incorrect faith and/or incorrect practice. Any or all of these abnormal "chromosomes" are present should one fail to attain Buddhahood in this life.
Just as deletions, inversions, translocations, additions, and mutations within chromasomes lead to various congenital defects or other diseases such as cancer, the same type of processes within the Buddhist believer leads to a life state other than Buddhahood. Nichiren states in the Kaimoku Sho,
"They will tear off the first part of the Sutra and stick it on the end, tear off the end and put it at the beginning, put the end and the beginning in the middle, and the beginning at the middle or end". This is analogous to inversions and translocations of the Law.
In The Supreme Leader Of The World, Nichiren states, "However they are alike in that they all abandoned Shakyamuni Buddha". This is analogous to deletion of the Original Buddha.
The Akimoto Gosho talks about four faults in a vessel (the vessel of our faith and practice) and explains that "The Lotus Sutra is the Dharma water of the Buddha's wisdom". Refusing to believe in or practice the Lotus Sutra or believe in Shakyamuni Buddha of the Juryo Chapter of the Lotus Sutra is having an overturned vessel of faith and practice. This is analogous to having a mutation in one's faith or practice.
Correct faith and practice are like the enzymes that serve to maintain correct functioning, maintenance, and repair of chromosomes and lead to a good outcome [Buddhahood].