A developmental approach to homology and brain evolution
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| Format: | Artículo científico |
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Sociedad de Biología de Chile
2010
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| _version_ | 1876468986738114560 |
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| author | FRANCISCO ABOITIZ |
| author_facet | FRANCISCO ABOITIZ |
| contents | A developmental approach to homology and brain evolution FRANCISCO ABOITIZ Biología pallium neocortex ventricular zone subventricular zone Dorsal ventricular ridge Although homology is central to evolutionary interpretations, establishing it has become a highly disputed issue in some instances. Here I argue 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. 2010 artículo científico 0716-078X https://www.redalyc.org/articulo.oa?id=369944296002 en http://www.redalyc.org/revista.oa?id=3699 Revista Chilena de Historia Natural application/pdf Sociedad de Biología de Chile Revista Chilena de Historia Natural (Chile) Num.4 Vol.83 |
| format | Artículo científico |
| id | redalyc_369944296002 |
| institution | Redalyc |
| language | en |
| publishDate | 2010 |
| publisher | Sociedad de Biología de Chile |
| spellingShingle | A developmental approach to homology and brain evolution FRANCISCO ABOITIZ Biología pallium neocortex ventricular zone subventricular zone Dorsal ventricular ridge A developmental approach to homology and brain evolution FRANCISCO ABOITIZ Biología pallium neocortex ventricular zone subventricular zone Dorsal ventricular ridge Although homology is central to evolutionary interpretations, establishing it has become a highly disputed issue in some instances. Here I argue 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. 2010 artículo científico 0716-078X https://www.redalyc.org/articulo.oa?id=369944296002 en http://www.redalyc.org/revista.oa?id=3699 Revista Chilena de Historia Natural application/pdf Sociedad de Biología de Chile Revista Chilena de Historia Natural (Chile) Num.4 Vol.83 |
| title | A developmental approach to homology and brain evolution |
| topic | Biología pallium neocortex ventricular zone subventricular zone Dorsal ventricular ridge |
| url | https://www.redalyc.org/articulo.oa?id=369944296002 |