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Updated: Jun 22, 2026
07:09
A Bioinformatics Pipeline for Investigating Molecular Evolution and Gene Expression using RNA-seq
Published on: May 28, 2021
Origin and evolution of operons and metabolic pathways
Marco Fondi1, Giovanni Emiliani, Renato Fani
1Laboratory of Microbial and Molecular Evolution, Department of Evolutionary Biology, Via Romana 17-19, University of Florence, 50125 Florence, Italy. marco.fondi@unifi.it
Research in Microbiology
|May 26, 2009
Summary
Metabolic pathways evolved to help early life forms create their own nutrients, reducing reliance on external sources. This review explores theories on how these pathways and prokaryotic operons originated and developed.
Area of Science:
- Biochemistry
- Evolutionary Biology
- Molecular Biology
Background:
- Metabolic pathways are fundamental to cellular life, enabling organisms to synthesize essential compounds.
- Early life evolved mechanisms to produce nutrients, decreasing dependence on environmental organic molecules.
Purpose of the Study:
- To review major theories on the assembly of metabolic pathways.
- To explore the origin and evolution of prokaryotic operons.
Main Methods:
- Literature review of existing theories.
- Synthesis of evolutionary and biochemical data.
Main Results:
- Discussion of key hypotheses regarding metabolic pathway emergence.
- Analysis of proposed models for prokaryotic operon evolution.
Conclusions:
- Metabolic pathway evolution was critical for early organismal independence.
- Understanding operon origins provides insight into early gene regulation.
Related Concept Videos
01:23Operon Model
The operon model represents a fundamental mechanism of gene regulation in prokaryotes, enabling coordinated expression of genes involved in related metabolic or functional pathways. Operons consist of structural genes, a promoter, and an operator, with transcription regulated by repressors, activators, and small effector molecules.Structure and Function of OperonsAn operon is a cluster of structural genes transcribed together under the control of a single promoter. The promoter region...
02:09Operons
Prokaryotes can control gene expression through operons—DNA sequences consisting of regulatory elements and clustered, functionally related protein-coding genes. Operons use a single promoter sequence to initiate transcription of a gene cluster (i.e., a group of structural genes) into a single mRNA molecule. The terminator sequence ends transcription. An operator sequence, located between the promoter and structural genes, prohibits the operon’s transcriptional activity if bound by a repressor...
02:09Operons
Prokaryotes can control gene expression through operons—DNA sequences consisting of regulatory elements and clustered, functionally related protein-coding genes. Operons use a single promoter sequence to initiate transcription of a gene cluster (i.e., a group of structural genes) into a single mRNA molecule. The terminator sequence ends transcription. An operator sequence, located between the promoter and structural genes, prohibits the operon’s transcriptional activity if bound by a repressor...
01:25Inducible Operons: lac Operon
The lac operon in Escherichia coli is a model for understanding inducible gene regulation and metabolic flexibility. It integrates local control by lactose and global regulation through catabolite repression, enabling E. coli to preferentially metabolize glucose when available and switch to lactose utilization when glucose is scarce.Structure and Function of the lac OperonThe lac operon contains three structural genes: lacZ (β-galactosidase), lacY (lactose permease), and lacA (thiogalactoside...
01:58Prokaryotic Transcriptional Activators and Repressors
The organization of prokaryotic genes in their genome is notably different from that of eukaryotes. Prokaryotic genes are organized, such that the genes for proteins involved in the same biochemical process or function are located together in groups. This group of genes, along with their regulatory elements, are collectively known as an operon. The functional genes in an operon are transcribed together to give a single strand of mRNA known as polycistronic mRNA.
Transcription of prokaryotic...
Transcription of prokaryotic...
01:58Prokaryotic Transcriptional Activators and Repressors
The organization of prokaryotic genes in their genome is notably different from that of eukaryotes. Prokaryotic genes are organized, such that the genes for proteins involved in the same biochemical process or function are located together in groups. This group of genes, along with their regulatory elements, are collectively known as an operon. The functional genes in an operon are transcribed together to give a single strand of mRNA known as polycistronic mRNA.
Transcription of prokaryotic...
Transcription of prokaryotic...