SCYNAPSIS
#evolution
#evolution
#evolution
Image credit by Pablo Ávalos Prado
Image credit by Pablo Ávalos Prado
Image credit by Pablo Ávalos Prado
Pablo Ávalos Prado
Pablo Ávalos Prado
Pablo Ávalos Prado
Neuroscientist & Medical Writer
Neuroscientist & Medical Writer
Neuroscientist & Medical Writer
April 12, 2023
April 12, 2023
April 12, 2023
The bacterial origin of the human eye from an evolutionary “point of view”
The bacterial origin of the human eye from an evolutionary “point of view”
The bacterial origin of the human eye from an evolutionary “point of view”
The human eye, like in all vertebrates, acts as a precise camera that detects different levels of light intensity thanks to the perfect synchronization of proteins in the retina. A new study has found that some of these proteins evolved originally from bacteria through a genetic transfer that took place more than 500 million years ago.
In the Origin of the species, Charles Darwin struggled to explain the evolutionary origin of an organ of “extreme perfection and complication” such as the human eye. Although 160 years ago the only source for evolutionary studies was a limited fossil record, current research compares the sequenced genome of species belonging to very distant domains of life, from animals to bacteria.
In this context, a research group from UC San Diego has compared more than 900 genomes looking for the origin of IRBP (interphotoreceptor retinoid-binding protein), a protein that allows vision in low light conditions, a unique feature of vertebrates. This study has found that this protein is very well conserved among all vertebrates, keeping the same function and sequence in birds, mammals, fish and amphibians.
However, IRBP does not have an animal origin: it was “borrowed” from bacteria. According to this work, before the diversification of vertebrates more than 500 million years ago, a bacterium transferred a gene with the basic IRBP sequence to the common ancestor of vertebrates. Following this “horizontal gene transfer” the bacterial gene duplicated and underwent serial modifications on its sequence until becoming the current IRBP of vertebrates, very different to its bacterial precursor.
The highly conserved sequence of IRBP in all vertebrates and the presence of a similar gene only restricted to a few species of fungi and plants discard the possibility of the evolution of a primitive IRBP originated from a common ancestor of all living organisms.
Therefore, bacteria should be considered a rich source of animal genes. Unlike evolution of existing genes, acquisition of bacterial genetic material by horizontal transfer represents an additional and “fast” evolutionary path that provides unique functions for specific phyla, just like “bacterial” IRBP promotes vision exclusively in vertebrates.
Original article
The human eye, like in all vertebrates, acts as a precise camera that detects different levels of light intensity thanks to the perfect synchronization of proteins in the retina. A new study has found that some of these proteins evolved originally from bacteria through a genetic transfer that took place more than 500 million years ago.
In the Origin of the species, Charles Darwin struggled to explain the evolutionary origin of an organ of “extreme perfection and complication” such as the human eye. Although 160 years ago the only source for evolutionary studies was a limited fossil record, current research compares the sequenced genome of species belonging to very distant domains of life, from animals to bacteria.
In this context, a research group from UC San Diego has compared more than 900 genomes looking for the origin of IRBP (interphotoreceptor retinoid-binding protein), a protein that allows vision in low light conditions, a unique feature of vertebrates. This study has found that this protein is very well conserved among all vertebrates, keeping the same function and sequence in birds, mammals, fish and amphibians.
However, IRBP does not have an animal origin: it was “borrowed” from bacteria. According to this work, before the diversification of vertebrates more than 500 million years ago, a bacterium transferred a gene with the basic IRBP sequence to the common ancestor of vertebrates. Following this “horizontal gene transfer” the bacterial gene duplicated and underwent serial modifications on its sequence until becoming the current IRBP of vertebrates, very different to its bacterial precursor.
The highly conserved sequence of IRBP in all vertebrates and the presence of a similar gene only restricted to a few species of fungi and plants discard the possibility of the evolution of a primitive IRBP originated from a common ancestor of all living organisms.
Therefore, bacteria should be considered a rich source of animal genes. Unlike evolution of existing genes, acquisition of bacterial genetic material by horizontal transfer represents an additional and “fast” evolutionary path that provides unique functions for specific phyla, just like “bacterial” IRBP promotes vision exclusively in vertebrates.
Original article
The human eye, like in all vertebrates, acts as a precise camera that detects different levels of light intensity thanks to the perfect synchronization of proteins in the retina. A new study has found that some of these proteins evolved originally from bacteria through a genetic transfer that took place more than 500 million years ago.
In the Origin of the species, Charles Darwin struggled to explain the evolutionary origin of an organ of “extreme perfection and complication” such as the human eye. Although 160 years ago the only source for evolutionary studies was a limited fossil record, current research compares the sequenced genome of species belonging to very distant domains of life, from animals to bacteria.
In this context, a research group from UC San Diego has compared more than 900 genomes looking for the origin of IRBP (interphotoreceptor retinoid-binding protein), a protein that allows vision in low light conditions, a unique feature of vertebrates. This study has found that this protein is very well conserved among all vertebrates, keeping the same function and sequence in birds, mammals, fish and amphibians.
However, IRBP does not have an animal origin: it was “borrowed” from bacteria. According to this work, before the diversification of vertebrates more than 500 million years ago, a bacterium transferred a gene with the basic IRBP sequence to the common ancestor of vertebrates. Following this “horizontal gene transfer” the bacterial gene duplicated and underwent serial modifications on its sequence until becoming the current IRBP of vertebrates, very different to its bacterial precursor.
The highly conserved sequence of IRBP in all vertebrates and the presence of a similar gene only restricted to a few species of fungi and plants discard the possibility of the evolution of a primitive IRBP originated from a common ancestor of all living organisms.
Therefore, bacteria should be considered a rich source of animal genes. Unlike evolution of existing genes, acquisition of bacterial genetic material by horizontal transfer represents an additional and “fast” evolutionary path that provides unique functions for specific phyla, just like “bacterial” IRBP promotes vision exclusively in vertebrates.
Original article