Describe an example of non-heritable variation. Think about the way an organism interacts with its environment and how that influences its phenotype (the nurture in nature vs. nurture). Knowing what you do about genetics, genes, and gene expression control, propose a mechanism of molecular control that might be working in the example you have chosen.

Epigenetic reprogramming

Explanation:

Epigenetic is a discipline that studies how phenotypic traits are influenced by DNA methylation and histone post-translational modifications such as acetylation, methylation and ribosilation. All these epigenetic marks are known to affect the conformation of the DNA molecule, thereby altering gene expression patterns and consequently also phenotypic associated traits. Epigenetic reprogramming refers to the erasure and remodeling of these epigenetic marks, this being a type of non-inherited variation produced by the interaction between a genotype and its environment. Epigenetic reprogramming is in part responsible for the non-heritable differences observed between different cell types and tissues.

"a.) well–developed vascular system."