What is the primary factor that causes phenotypic differences in clones?

Phenotypic differences in clones are primarily attributed to environmental factors. While clones originate from the same genetic material and are thus initially genetically identical, their phenotypic expression can be dramatically influenced by the environment they are exposed to. This includes variations in temperature, humidity, light exposure, nutrient availability, and even the presence of pests or diseases.

For instance, two plants that are genetically identical (clones) can exhibit differing heights, leaf sizes, or resistance to diseases if they are grown in different soil types or climatic conditions. These environmental influences can activate or silence certain genes, leading to observable differences in phenotype despite the genetic uniformity of the clones.

While dietary differences can affect the growth of organisms, particularly in animals, it is the overarching environmental context in which these organisms develop that fundamentally shapes their phenotypic outcomes. Age can also play a role, but in the specific context of clones, it is not a primary factor as all clones start from the same age at the point of creation.