Variation is function: Are single cell differences functionally important?: Testing the hypothesis that single cell variation is required for aggregate function

Bioessays. 2016 Feb;38(2):172-80. doi: 10.1002/bies.201500124. Epub 2015 Dec 2.


There is a growing appreciation of the extent of transcriptome variation across individual cells of the same cell type. While expression variation may be a byproduct of, for example, dynamic or homeostatic processes, here we consider whether single-cell molecular variation per se might be crucial for population-level function. Under this hypothesis, molecular variation indicates a diversity of hidden functional capacities within an ensemble of identical cells, and this functional diversity facilitates collective behavior that would be inaccessible to a homogenous population. In reviewing this topic, we explore possible functions that might be carried by a heterogeneous ensemble of cells; however, this question has proven difficult to test, both because methods to manipulate molecular variation are limited and because it is complicated to define, and measure, population-level function. We consider several possible methods to further pursue the hypothesis that variation is function through the use of comparative analysis and novel experimental techniques.

Keywords: bet-hedging; evolution of variation; fractional response; functional variation; single cell transcriptome; single cell variation.

Publication types

  • Review

MeSH terms

  • Animals
  • Genetic Variation / genetics*
  • Genetic Variation / physiology*
  • Humans
  • Transcriptome / genetics*
  • Transcriptome / physiology*