The Small World of Adult Hippocampal Neurogenesis

Making mechanistic sense of genetically complex biological systems such as adult hippocampal neurogenesis poses conceptual and many practical challenges. Transcriptomics studies have helped to move beyond single-gene approaches and have greatly enhanced the accessibility to effects of greater number...

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Main Authors: Rupert W. Overall, Gerd Kempermann
Format: Article
Language:English
Published: Frontiers Media S.A. 2018-09-01
Series:Frontiers in Neuroscience
Subjects:
Online Access:https://www.frontiersin.org/article/10.3389/fnins.2018.00641/full
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author Rupert W. Overall
Rupert W. Overall
Gerd Kempermann
Gerd Kempermann
author_facet Rupert W. Overall
Rupert W. Overall
Gerd Kempermann
Gerd Kempermann
author_sort Rupert W. Overall
collection DOAJ
description Making mechanistic sense of genetically complex biological systems such as adult hippocampal neurogenesis poses conceptual and many practical challenges. Transcriptomics studies have helped to move beyond single-gene approaches and have greatly enhanced the accessibility to effects of greater numbers of genes. Typically, however, the number of experimental conditions compared is small and the conclusions remain correspondingly limited. In contrast, studying complex traits in genetic reference populations, in which genetic influences are varied systematically, provides insight into the architecture of relationships between phenotypes and putative molecular mechanisms. We describe that the correlation network among transcripts that builds around the adult neurogenesis phenotype and its endophenotypes is, as expected, a small-world network and scale free. The high degree of connectivity implies that adult neurogenesis is essentially an “omnigenic” process. From any gene of interest, a link to adult hippocampal neurogenesis can be constructed in just a few steps. We show that, at a minimum correlation of 0.6, the hippocampal transcriptome network associated with adult neurogenesis exhibits only two “degrees of separation.” This fact has many interesting consequences for our attempts to unravel the (molecular) causality structure underlying adult neurogenesis and other complex biological systems. Our article is not written with the expert on network theory in mind but rather aims to raise interest among neurobiologists, active in neurogenesis and related fields, in network theory and analysis as a set of tools that hold great promise for coping with the study of “omnigenic” phenotypes and systems.
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spelling doaj.art-88a36bd8b52c4e72a35f54ce8452ffd82022-12-21T22:54:42ZengFrontiers Media S.A.Frontiers in Neuroscience1662-453X2018-09-011210.3389/fnins.2018.00641407354The Small World of Adult Hippocampal NeurogenesisRupert W. Overall0Rupert W. Overall1Gerd Kempermann2Gerd Kempermann3German Center for Neurodegenerative Diseases (DZNE), Dresden, GermanyCenter for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, GermanyGerman Center for Neurodegenerative Diseases (DZNE), Dresden, GermanyCenter for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, GermanyMaking mechanistic sense of genetically complex biological systems such as adult hippocampal neurogenesis poses conceptual and many practical challenges. Transcriptomics studies have helped to move beyond single-gene approaches and have greatly enhanced the accessibility to effects of greater numbers of genes. Typically, however, the number of experimental conditions compared is small and the conclusions remain correspondingly limited. In contrast, studying complex traits in genetic reference populations, in which genetic influences are varied systematically, provides insight into the architecture of relationships between phenotypes and putative molecular mechanisms. We describe that the correlation network among transcripts that builds around the adult neurogenesis phenotype and its endophenotypes is, as expected, a small-world network and scale free. The high degree of connectivity implies that adult neurogenesis is essentially an “omnigenic” process. From any gene of interest, a link to adult hippocampal neurogenesis can be constructed in just a few steps. We show that, at a minimum correlation of 0.6, the hippocampal transcriptome network associated with adult neurogenesis exhibits only two “degrees of separation.” This fact has many interesting consequences for our attempts to unravel the (molecular) causality structure underlying adult neurogenesis and other complex biological systems. Our article is not written with the expert on network theory in mind but rather aims to raise interest among neurobiologists, active in neurogenesis and related fields, in network theory and analysis as a set of tools that hold great promise for coping with the study of “omnigenic” phenotypes and systems.https://www.frontiersin.org/article/10.3389/fnins.2018.00641/fulltranscriptomicsgeneticsgene networksgenetic reference panelstem cells
spellingShingle Rupert W. Overall
Rupert W. Overall
Gerd Kempermann
Gerd Kempermann
The Small World of Adult Hippocampal Neurogenesis
Frontiers in Neuroscience
transcriptomics
genetics
gene networks
genetic reference panel
stem cells
title The Small World of Adult Hippocampal Neurogenesis
title_full The Small World of Adult Hippocampal Neurogenesis
title_fullStr The Small World of Adult Hippocampal Neurogenesis
title_full_unstemmed The Small World of Adult Hippocampal Neurogenesis
title_short The Small World of Adult Hippocampal Neurogenesis
title_sort small world of adult hippocampal neurogenesis
topic transcriptomics
genetics
gene networks
genetic reference panel
stem cells
url https://www.frontiersin.org/article/10.3389/fnins.2018.00641/full
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