What does the Allen Gene Expression Atlas tell us about mouse brain evolution?

TL;DR

This study leverages gene expression data and ortholog datasets to analyze mouse brain evolution, revealing region-specific gene expression patterns linked to evolutionary timelines, and introduces new quantitative tools for comparative neuroanatomy.

Contribution

It introduces a novel molecular approach to study brain evolution by integrating gene expression profiles with phylogenetic data, enhancing understanding of neuroanatomical development.

Findings

Brain regions show over-representation of genes from specific evolutionary periods.

Gene expression profiles can distinguish brain regions based on evolutionary age.

The approach complements existing neuroanatomical knowledge with quantitative molecular data.

Abstract

We use the Allen Gene Expression Atlas (AGEA) and the OMA ortholog dataset to investigate the evolution of mouse-brain neuroanatomy from the standpoint of the molecular evolution of brain-specific genes. For each such gene, using the phylogenetic tree for all fully sequenced species and the presence of orthologs of the gene in these species, we construct and assign a discrete measure of evolutionary age. The gene expression profile of all gene of similar age, relative to the average gene expression profile, distinguish regions of the brain that are over-represented in the corresponding evolutionary timescale. We argue that the conclusions one can draw on evolution of twelve major brain regions from such a molecular level analysis supplements existing knowledge of mouse brain evolution and introduces new quantitative tools, especially for comparative studies, when AGEA-like data sets for other species become available. Using the functional role of the genes representational of a certain evolutionary timescale and brain region we compare and contrast, wherever possible, our observations with existing knowledge in evolutionary neuroanatomy.