Developmental genetic evidence for a monophyletic origin of the bilaterian brain

H. Reichert, A. Simeone

Research output: Contribution to journalArticle

Abstract

The widely held notion of an independent evolutionary origin of invertebrate and vertebrate brains is based on classical phylogenetic, neuroanatomical and embryological data. The interpretation of these data in favour of a polyphyletic origin of animals brains is currently being challenged by three fundamental findings that derive from comparative molecular, genetic and developmental analyses. First, modern molecular systematics indicates that none of the extant animals correspond to evolutionary intermediates between the protostomes and the deuterostomes, thus making it impossible to deduce the morphological organization of the ancestral bilaterian or its brain from living species. Second, recent molecular genetic evidence for the body axis inversion hypothesis now supports the idea that the basic body plan of vertebrates and invertebrates is similar but inverted, suggesting that the ventral nerve chord of protostome invertebrates is homologous to the dorsal nerve cord of deuterostome chordates. Third, a developmental genetic analysis of the molecular control elements involved in early embryonic brain patterning is uncovering the existence of structurally and functionally homologous genes that have comparable and interchangeable functions in key aspects of brain development in invertebrate and vertebrate model systems. All three of these findings are compatible with the hypothesis of a monophyletic origin of the bilaterian brain. Here we review these findings and consider their significance and implications for current thinking on the evolutionary origin of bilaterian brains. We also preview the impact of comparative functional genomic analyses on our understanding of brain evolution.

Original languageEnglish
Pages (from-to)1533-1544
Number of pages12
JournalPhilosophical transactions of the Royal Society of London. Series B: Biological sciences
Volume356
Issue number1414
DOIs
Publication statusPublished - Oct 29 2001

Fingerprint

brain
Brain
Invertebrates
invertebrate
invertebrates
Vertebrates
Molecular Biology
vertebrate
vertebrates
molecular genetics
nerve tissue
Animals
Chordata
molecular systematics
animal
genetic analysis
genetic techniques and protocols
animals
genomics
Genes

Keywords

  • Brain development
  • Brain evolution
  • Drosophila
  • Hox genes
  • Otx
  • Urbilateria

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Agricultural and Biological Sciences (miscellaneous)

Cite this

Developmental genetic evidence for a monophyletic origin of the bilaterian brain. / Reichert, H.; Simeone, A.

In: Philosophical transactions of the Royal Society of London. Series B: Biological sciences, Vol. 356, No. 1414, 29.10.2001, p. 1533-1544.

Research output: Contribution to journalArticle

@article{22b0bbf90f35492ba073635a924da895,
title = "Developmental genetic evidence for a monophyletic origin of the bilaterian brain",
abstract = "The widely held notion of an independent evolutionary origin of invertebrate and vertebrate brains is based on classical phylogenetic, neuroanatomical and embryological data. The interpretation of these data in favour of a polyphyletic origin of animals brains is currently being challenged by three fundamental findings that derive from comparative molecular, genetic and developmental analyses. First, modern molecular systematics indicates that none of the extant animals correspond to evolutionary intermediates between the protostomes and the deuterostomes, thus making it impossible to deduce the morphological organization of the ancestral bilaterian or its brain from living species. Second, recent molecular genetic evidence for the body axis inversion hypothesis now supports the idea that the basic body plan of vertebrates and invertebrates is similar but inverted, suggesting that the ventral nerve chord of protostome invertebrates is homologous to the dorsal nerve cord of deuterostome chordates. Third, a developmental genetic analysis of the molecular control elements involved in early embryonic brain patterning is uncovering the existence of structurally and functionally homologous genes that have comparable and interchangeable functions in key aspects of brain development in invertebrate and vertebrate model systems. All three of these findings are compatible with the hypothesis of a monophyletic origin of the bilaterian brain. Here we review these findings and consider their significance and implications for current thinking on the evolutionary origin of bilaterian brains. We also preview the impact of comparative functional genomic analyses on our understanding of brain evolution.",
keywords = "Brain development, Brain evolution, Drosophila, Hox genes, Otx, Urbilateria",
author = "H. Reichert and A. Simeone",
year = "2001",
month = "10",
day = "29",
doi = "10.1098/rstb.2001.0972",
language = "English",
volume = "356",
pages = "1533--1544",
journal = "Philosophical Transactions of the Royal Society B: Biological Sciences",
issn = "0962-8436",
publisher = "Royal Society of London",
number = "1414",

}

TY - JOUR

T1 - Developmental genetic evidence for a monophyletic origin of the bilaterian brain

AU - Reichert, H.

AU - Simeone, A.

PY - 2001/10/29

Y1 - 2001/10/29

N2 - The widely held notion of an independent evolutionary origin of invertebrate and vertebrate brains is based on classical phylogenetic, neuroanatomical and embryological data. The interpretation of these data in favour of a polyphyletic origin of animals brains is currently being challenged by three fundamental findings that derive from comparative molecular, genetic and developmental analyses. First, modern molecular systematics indicates that none of the extant animals correspond to evolutionary intermediates between the protostomes and the deuterostomes, thus making it impossible to deduce the morphological organization of the ancestral bilaterian or its brain from living species. Second, recent molecular genetic evidence for the body axis inversion hypothesis now supports the idea that the basic body plan of vertebrates and invertebrates is similar but inverted, suggesting that the ventral nerve chord of protostome invertebrates is homologous to the dorsal nerve cord of deuterostome chordates. Third, a developmental genetic analysis of the molecular control elements involved in early embryonic brain patterning is uncovering the existence of structurally and functionally homologous genes that have comparable and interchangeable functions in key aspects of brain development in invertebrate and vertebrate model systems. All three of these findings are compatible with the hypothesis of a monophyletic origin of the bilaterian brain. Here we review these findings and consider their significance and implications for current thinking on the evolutionary origin of bilaterian brains. We also preview the impact of comparative functional genomic analyses on our understanding of brain evolution.

AB - The widely held notion of an independent evolutionary origin of invertebrate and vertebrate brains is based on classical phylogenetic, neuroanatomical and embryological data. The interpretation of these data in favour of a polyphyletic origin of animals brains is currently being challenged by three fundamental findings that derive from comparative molecular, genetic and developmental analyses. First, modern molecular systematics indicates that none of the extant animals correspond to evolutionary intermediates between the protostomes and the deuterostomes, thus making it impossible to deduce the morphological organization of the ancestral bilaterian or its brain from living species. Second, recent molecular genetic evidence for the body axis inversion hypothesis now supports the idea that the basic body plan of vertebrates and invertebrates is similar but inverted, suggesting that the ventral nerve chord of protostome invertebrates is homologous to the dorsal nerve cord of deuterostome chordates. Third, a developmental genetic analysis of the molecular control elements involved in early embryonic brain patterning is uncovering the existence of structurally and functionally homologous genes that have comparable and interchangeable functions in key aspects of brain development in invertebrate and vertebrate model systems. All three of these findings are compatible with the hypothesis of a monophyletic origin of the bilaterian brain. Here we review these findings and consider their significance and implications for current thinking on the evolutionary origin of bilaterian brains. We also preview the impact of comparative functional genomic analyses on our understanding of brain evolution.

KW - Brain development

KW - Brain evolution

KW - Drosophila

KW - Hox genes

KW - Otx

KW - Urbilateria

UR - http://www.scopus.com/inward/record.url?scp=0035968925&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0035968925&partnerID=8YFLogxK

U2 - 10.1098/rstb.2001.0972

DO - 10.1098/rstb.2001.0972

M3 - Article

C2 - 11604121

AN - SCOPUS:0035968925

VL - 356

SP - 1533

EP - 1544

JO - Philosophical Transactions of the Royal Society B: Biological Sciences

JF - Philosophical Transactions of the Royal Society B: Biological Sciences

SN - 0962-8436

IS - 1414

ER -