The MetaPersona smart contract is a simplified model of human genome on blockchain! We made a simple model of human chromosomes and then implemented it in solidity, each modeled human is called a Persona and each Persona is an NFT, we used Multi Token Standard (ERC-1155) for this project so we could handle fungible and non-fungible tokens at same time with one contract. Lets first check some preliminary facts about chromosomes and then we'll get back to the MetaPersona.
Humans have 23 pair of chromosomes, 22 first pair of them are clled autosomes and both men and women have them, the 23rd pair are called sex chromosomes, females have 2 X chromosomes (XX) while men have one X and one Y chromosome (XY). Chromosomes are strands of DNA which itself consists of base pairs (double stranded dna), each base pair could have 4 combination (AT, TA, GC and CG). We all get our chromosomes from our parents, and we get one chromosome from each of our parents and inherit the genetical data from them, at meiosis, the chromosomes go through some steps and make gametes and then a gamete from male and a gamete from female could make a zygote and so on and so forth... There are rougly around 3 billion base pairs in human genome, each base pair has 4 possible combination so if we want to make a better model we need to have 3e9 * 2 bits to save the possible base pairs, this is the minimum amount for a basic model which by the way does not consider the MT base pairs. This was a very very concise description of the chromosomes and the way they combine to make a human being.
We modeled chromosomes as structs in solidity a chromosome struct is
struct Chromosome {
uint256[37] autosomes;
uint256[2] x;
uint192 y;
}Our modeled chromosomes has a length of 10176 bits, this length is proportional to the real human chromosomes (that 3e9 base pairs), for arriving at this length we took the chromosome 21 as the reference chromosome and then calculated the length of other chromosomes according to their real length, then bucketized (devidable by 8) the values in uint256 and created the chromosome struct.
The MetaPersona.s.sol deploys the contract and then runs a genesis function to make the Adam (male persona) and Eve (female persona) and mints them for contract deployer. then contract deployer could use spawn function to make new personas for himself/herself or for a _receiver address,
If anyone own two male and female Personas, then they could call the spawn function to spawn a new Persona. There are two spawn functions in the contract, one of them is only could be called by someone with SPAWN_ROLE, since the amount of calculation and data saving is alot in this contract, we made a companion api to lower the gas cost for Persona spawning, the meiosis (and crossover of chromosomes) are done offchain and then the web api spawns the Persona for requester, this way we lowered the gas cost by 50% comparing to onchain spawning.
Users could stake their Personas for some METAPERSONA token, the amount of METAPERSONA token generated for Personas is different and it depends on their genes, when a Persona is staked, it cannot spawn a new Persona. Users could use the METAPERSONA rewards to pay for fees and use it in Life Forge.
Not all users could have a pair of male and female Personas to spawn a new Persona, so they can use Life Forge, users could add their Personas to Life Forge to get some METAPERSONA tokens, and other users could pay them to spawn a new Persona using their Persona.
All functionality is implemented in the smart contract and tests are written to check them, everyone could call external functions of the smart contract. There's a website which is designed using Blazor wasm, but it's not ready yet. The code for website and webapi is available in their respective repos. Both web and webapi projects could be deployed using docker, simply call the following command in the root of each project to build and compose them.
$ docker compose up -dThe api is deployed to this address and it could be tested, e.g. call the following public anonymous endpoint to get the contract address
$ curl https://metapersona.fun/api/metapersona/contract