Cell culture methods and compositions

A method comprising:

• (i) maintaining a cell in vitro, by performing a method comprising the steps of:
• providing a cell of interest in cell culture;
• determining differential breadth of histone 3 trimethylated at lysine 4 (H3K4me3) modified regions for each protein-coding gene in said cell;
• determining a differential broadness score (DBS) for each protein-coding gene in said cell;
• determining a network score for each protein-coding gene in said cell based on the DBS and interactions between the protein products of each protein-coding gene over at least one network,
• determining a cell identity score (RegDBS) for each protein-coding gene in said cell based on a combination of the DBS and network scores;
• prioritising each protein-coding gene according to its RegDBS thereby identifying cell identity genes for said cell, wherein each cell identity gene encodes a factor associated with cell identity of the cell of interest;
• contacting said cell of interest with one or more of the factors associated with the cell identity of said cell;
• culturing said cell of interest for a sufficient time and under conditions to allow for maintenance of said cell in cell culture;
• thereby maintaining the cell of interest in vitro;
• and
• (ii) administering the cell of interest to an individual, or administering a population of cells, wherein at least 5% of cells exhibit at least one characteristic of the cell of interest and those cells are produced by a method according to (i), to an individual.