A developmental approach to homology and brain evolution

Although homology is central to evolutionary interpretations, establishing it has become a highly disputed issue in some instances. Here I argüe for a developmental understanding of evolution, where modifications of the developmental programs are a key source of evolutionary novelty. Although this p...

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Autor principal:	ABOITIZ,FRANCISCO
Lenguaje:	English
Publicado:	Sociedad de Biología de Chile 2010
Materias:	dorsal ventricular ridge neocortex pallium subventricular zone ventricular zone
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2010000400002
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spelling	oai:scielo:S0716-078X20100004000022011-04-08A developmental approach to homology and brain evolutionABOITIZ,FRANCISCO dorsal ventricular ridge neocortex pallium subventricular zone ventricular zone Although homology is central to evolutionary interpretations, establishing it has become a highly disputed issue in some instances. Here I argüe for a developmental understanding of evolution, where modifications of the developmental programs are a key source of evolutionary novelty. Although this perspective is not new, in comparative neurobiology it has remained controversial. Specifically, the evolutionary origin of the mammalian neocortex has been a particularly debated point. I propose a perspective that could help reconcile a long standing controversy: either the mammalian neocortex corresponds as a whole to the dorsal hemisphere of reptiles and birds, or alternatively its lateral aspect corresponds to the lateral cerebral hemisphere and is partly homologous to the dorsal ventricular ridge (DVR), a brain mass that receives the bulk of sensory input in reptiles and birds. Genetic and embryonic evidence strongly favor a dorsal origin for the whole neocortex, while the DVR derives from the lateral hemisphere. Nevertheless, the phylogenetically new elements of both the neocortex and the avian DVR derive largely from intermediate progenitor cells located in the embryonic subventricular zone (SVZ), a zone of late proliferating activity located deep to the ventral, the lateral and the dorsal hemisphere. I suggest that, despite originating in different embryonic regions (lateral vs. dorsal hemisphere), the evolutionary new cellular elements in both the avian brain and in the mammalian neocortex derive from the activation of a similar genetic pathway, possibly activated by the gene Pax-6, that induces the late proliferation of embryonic neural progenitors. This pathway can be ancestral to amniotes, reflecting genetic homology. In mammals and birds independently, this precursor proliferative activity differentiated into an SVZ, recruiting neuronal precursors from different parts of the cerebral hemisphere in each group, to contribute to brain expansion.info:eu-repo/semantics/openAccessSociedad de Biología de ChileRevista chilena de historia natural v.83 n.4 20102010-12-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2010000400002en10.4067/S0716-078X2010000400002
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	dorsal ventricular ridge neocortex pallium subventricular zone ventricular zone
spellingShingle	dorsal ventricular ridge neocortex pallium subventricular zone ventricular zone ABOITIZ,FRANCISCO A developmental approach to homology and brain evolution
description	Although homology is central to evolutionary interpretations, establishing it has become a highly disputed issue in some instances. Here I argüe for a developmental understanding of evolution, where modifications of the developmental programs are a key source of evolutionary novelty. Although this perspective is not new, in comparative neurobiology it has remained controversial. Specifically, the evolutionary origin of the mammalian neocortex has been a particularly debated point. I propose a perspective that could help reconcile a long standing controversy: either the mammalian neocortex corresponds as a whole to the dorsal hemisphere of reptiles and birds, or alternatively its lateral aspect corresponds to the lateral cerebral hemisphere and is partly homologous to the dorsal ventricular ridge (DVR), a brain mass that receives the bulk of sensory input in reptiles and birds. Genetic and embryonic evidence strongly favor a dorsal origin for the whole neocortex, while the DVR derives from the lateral hemisphere. Nevertheless, the phylogenetically new elements of both the neocortex and the avian DVR derive largely from intermediate progenitor cells located in the embryonic subventricular zone (SVZ), a zone of late proliferating activity located deep to the ventral, the lateral and the dorsal hemisphere. I suggest that, despite originating in different embryonic regions (lateral vs. dorsal hemisphere), the evolutionary new cellular elements in both the avian brain and in the mammalian neocortex derive from the activation of a similar genetic pathway, possibly activated by the gene Pax-6, that induces the late proliferation of embryonic neural progenitors. This pathway can be ancestral to amniotes, reflecting genetic homology. In mammals and birds independently, this precursor proliferative activity differentiated into an SVZ, recruiting neuronal precursors from different parts of the cerebral hemisphere in each group, to contribute to brain expansion.
author	ABOITIZ,FRANCISCO
author_facet	ABOITIZ,FRANCISCO
author_sort	ABOITIZ,FRANCISCO
title	A developmental approach to homology and brain evolution
title_short	A developmental approach to homology and brain evolution
title_full	A developmental approach to homology and brain evolution
title_fullStr	A developmental approach to homology and brain evolution
title_full_unstemmed	A developmental approach to homology and brain evolution
title_sort	developmental approach to homology and brain evolution
publisher	Sociedad de Biología de Chile
publishDate	2010
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2010000400002
work_keys_str_mv	AT aboitizfrancisco adevelopmentalapproachtohomologyandbrainevolution AT aboitizfrancisco developmentalapproachtohomologyandbrainevolution
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A developmental approach to homology and brain evolution

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