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Evolution of Microbial Genome

Evolution of Microbial Genome

Microbial genome evolution is a highly dynamic process shaped by continual gene gain and loss across species and strains. This genomic flexibility allows microorganisms to adapt rapidly to environmental pressures and interactions with other organisms. Central to understanding this diversity is the distinction between the core and pan genomes.The core genome comprises the genes shared by all sampled strains of a species, representing essential functions needed for fundamental cellular processes.

Genome Size and the Evolution of New Genes

Genome Size and the Evolution of New Genes

While every living organism has a genome of some kind (be it RNA, or DNA), there is considerable variation in the sizes of these blueprints. One major factor that impacts genome size is whether the organism is prokaryotic or eukaryotic. In prokaryotes, the genome contains little to no non-coding sequence, such that genes are tightly clustered in groups or operons sequentially along the chromosome. Conversely, the genes in eukaryotes are punctuated by long stretches of non-coding sequence.

Genome Size and the Evolution of New Genes

Genome Size and the Evolution of New Genes

While every living organism has a genome of some kind (be it RNA, or DNA), there is considerable variation in the sizes of these blueprints. One major factor that impacts genome size is whether the organism is prokaryotic or eukaryotic. In prokaryotes, the genome contains little to no non-coding sequence, such that genes are tightly clustered in groups or operons sequentially along the chromosome. Conversely, the genes in eukaryotes are punctuated by long stretches of non-coding sequence.

Gene Evolution - Fast or Slow?

Gene Evolution - Fast or Slow?

The genomes of eukaryotes are punctuated by long stretches of sequence which do not code for proteins or RNAs. Although some of these regions do contain crucial regulatory sequences, the vast majority of this DNA serves no known function. Typically, these regions of the genome are the ones in which the fastest change, in evolutionary terms, is observed, because there is typically little to no selection pressure acting on these regions to preserve their sequences.
In contrast, regions which code...

Gene Evolution - Fast or Slow?

Gene Evolution - Fast or Slow?

The genomes of eukaryotes are punctuated by long stretches of sequence which do not code for proteins or RNAs. Although some of these regions do contain crucial regulatory sequences, the vast majority of this DNA serves no known function. Typically, these regions of the genome are the ones in which the fastest change, in evolutionary terms, is observed, because there is typically little to no selection pressure acting on these regions to preserve their sequences.
In contrast, regions which code...

Eukaryotic Evolution

Eukaryotic Evolution

The endosymbiont theory is the most widely accepted theory of eukaryotic evolution; however, its progression is still somewhat debated. According to the nucleus-first hypothesis, the ancestral prokaryote first evolved a membrane to enclose DNA and form the nucleus. Conversely, the mitochondria-first hypothesis suggests that the nucleus was formed after endosymbiosis of mitochondria.
Contrary to the endosymbiont theory, the eukaryote-first hypothesis proposes that the simpler prokaryotic and...

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Updated: May 31, 2026

Adaptation at the Extremes of Life: Experimental Evolution with the Extremophile Archaeon Sulfolobus acidocaldarius

Adaptation at the Extremes of Life: Experimental Evolution with the Extremophile Archaeon Sulfolobus acidocaldarius

Published on: June 14, 2024

Dinoflagellate genome evolution.

Jennifer H Wisecaver¹, Jeremiah D Hackett

¹Ecology and Evolutionary Biology Department, University of Arizona, Tucson, Arizona 85721, USA. hackettj@email.arizona.edu

Annual Review of Microbiology

|June 21, 2011

Summary

This summary is machine-generated.

Dinoflagellates, vital marine microbes, exhibit unique genomic traits like massive genomes and unusual gene arrangements. Advanced sequencing reveals insights into their complex evolution and biology.

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Area of Science:

Microbial Eukaryotic Genomics
Marine Biology
Evolutionary Biology

Background:

Dinoflagellates are ecologically significant microbial eukaryotes.
They possess exceptionally large nuclear genomes and unique chromosomal structures.
Their mitochondrial and plastid genomes are notably gene-poor.

Purpose of the Study:

To explore the novel genomic characteristics of dinoflagellates.
To understand the evolutionary influences, including gene transfer, on dinoflagellate genomes.
To leverage next-generation sequencing for genome-scale analyses.

Main Methods:

Utilizing next-generation sequencing technologies for genome-scale analysis.
Investigating gene arrangement in tandem arrays.
Analyzing messenger RNA trans-splicing mechanisms.

Main Results:

Discovery of genes in tandem arrays and trans-splicing in dinoflagellates.
Identification of a reduced role for transcriptional regulation.
Evidence of significant gene transfer events (lateral and endosymbiotic).

Conclusions:

Dinoflagellate genomes display unique features shaped by extensive gene transfer.
Modern sequencing technologies are crucial for unraveling dinoflagellate biology and evolution.
Further research is needed to fully understand this enigmatic group.