Collective properties of cellular identity: a computational approach

TL;DR

This paper explores the continuous spectrum of gene expression across different cell types using computational methods, aiming to better understand cellular identity beyond discrete classifications.

Contribution

It introduces a computational framework combining diversity sampling, gene separability, and soft classification to analyze cellular gene expression spectra.

Findings

Gene expression diversity varies continuously across cell types.

A priori cell types may not fully capture underlying cellular heterogeneity.

The methods improve understanding of cellular identity and subtype distinctions.

Abstract

Cell type (e.g. pluripotent cell, fibroblast) is the end result of many complex processes that unfold due to evolutionary, developmental, and transformational stimuli. A cell's phenotype and the discrete, a priori states that define various cell subtypes (e.g. skin fibroblast, embryonic stem cell) are ultimately part of a continuum that may predict changes and systematic variation in cell subtypes. These features can be both observable in existing cellular states and hypothetical (e.g. unobserved). In this paper, a series of approaches will be used to approximate the continuous diversity of gene expression across a series of pluripotent, totipotent, and fibroblast cellular subtypes. We will use a series of previously-collected datasets and analyze them using three complementary approaches: the computation of distances based on the subsampling of diversity, assessing the separability of individual genes for a specific cell line both within and between cell types, and a hierarchical soft classification technique that will assign a membership value for specific genes in specific cell types given a number of different criteria. These approaches will allow us to assess the observed gene-expression diversity in these datasets, as well as assess how well a priori cell types characterize their constituent populations. In conclusion, the application of these findings to a broader biological context will be discussed.