Gene expression analysis reveals the tipping points during infant brain development for human and chimpanzee

Hui Tang,Tao Zeng,Ying Tang,Luonan Chen

doi:10.1186/s12864-020-6465-8

Abstract

BackgroundPostpartum developmental delay has been proposed as an important phenotype of human evolution which contributes to many human-specific features including the increase in brain size and the advanced human-specific cognitive traits. However, the biological processes and molecular functions underlying early brain development still remain poorly understood, especially in human and primates.ResultsIn this paper, we comparatively and extensively studied dorsolarteral prefrontal cortex expression data in human and chimpanzee to investigate the critical processes or biological events during early brain development at a molecular level. By using the dynamic network biomarker (DNB) model, we found that there are tipping points around 3 months and 1 month, which are crucial periods in infant human and chimpanzee brain development, respectively. In particular, we shown that the human postnatal development and the corresponding expression changes are delayed 3 times relative to chimpanzee, and we also revealed that many common biological processes are highly involved in those critical periods for both human and chimpanzee, e.g., physiological system development functions, nervous system development, organismal development and tissue morphology. These findings support that the maximal rates of brain growth will be in those two critical periods for respective human and primates. In addition, different from chimpanzee, our analytic results also showed that human can further develop a number of advanced behavior functions around this tipping point (around 3 months), such as the ability of learning and memory.ConclusionThis work not only provides biological insights into primate brain development at a molecular level but also opens a new way to study the criticality of nonlinear biological processes based on the observed omics data.

Highlights

Postpartum developmental delay has been proposed as an important phenotype of human evolution which contributes to many human-specific features including the increase in brain size and the advanced humanspecific cognitive traits
Developmental retardation or neoteny has been identified and the brain developmental changes have been delayed comparing to other primate species
We focus on the analyses of infant brain development of human and chimpanzee, i.e. focusing on the early / first year life stages of humans and chimpanzees

Summary

Introduction

Postpartum developmental delay has been proposed as an important phenotype of human evolution which contributes to many human-specific features including the increase in brain size and the advanced humanspecific cognitive traits. The biological processes and molecular functions underlying early brain development still remain poorly understood, especially in human and primates. The primate brain development was traditionally studied by investigating the conserved biological processes and functions across mammals [1]. Tang et al BMC Genomics 2020, 21(Suppl 1): conducted at a molecular level. Results from these comparisons demonstrate that some human features may be explained by neoteny, e.g. small jaws [11]. Developmental retardation or neoteny has been identified and the brain developmental changes have been delayed comparing to other primate species. The infant structural growth rate changes approximately from 1%/d to 0.4%/d at the end of 3 months [12]. The brain-growth rate of infant chimpanzee is three times as much as that of human

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