Chimaeral rearrangement can take place in the germline if the mutation is in chloroplast in a single cell. A nuclear mutation can only lead to a chimaera directly if happening at the stage that the organism already has two or more cells. Meiotic recombination occurs during formation of pollen and egg cells with a high frequency. So, if the parents are not homozygous, i.e. , have several genes in two different forms, this may lead to new combinations in the offspring due to segregation. A plant with the dominant yellow mutation will make pollen and egg cells with a gene for green or a gene for yellow.
Mutation can also take place during seed formation but only with very low frequency.
Although meristem culture is only an artificial way of vegetive propagation there are a few differences. In meristem culture the neat order of layers is easily disturbed. This leads to chimaeral rearrangements with much higher frequency than in a garden. Also the mutation frequency might be higher as the whole metabolism can be upset, but usually it will be a rare event. Yellow plants are, as far as is known, nearly always due to a nuclear mutation.