Intron Invasions Trace Algal Speciation and Reveal Nearly Identical Arctic and Antarctic Micromonas Populations
Spliceosomal introns are a hallmark of eukaryotic genes that are hypothesized to play important roles in genome evolution but have poorly understood origins. Although most introns lack sequence homology to each other, new families of spliceosomal introns that are repeated hundreds of times in indivi...
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ftcdlib:oai:escholarship.org:ark:/13030/qt77k998gg 2023-09-05T13:12:56+02:00 Intron Invasions Trace Algal Speciation and Reveal Nearly Identical Arctic and Antarctic Micromonas Populations Simmons, Melinda P Bachy, Charles Sudek, Sebastian van Baren, Marijke J Sudek, Lisa Ares, Manuel Worden, Alexandra Z 2219 - 2235 2015-09-01 https://escholarship.org/uc/item/77k998gg unknown eScholarship, University of California qt77k998gg https://escholarship.org/uc/item/77k998gg public Molecular Biology and Evolution, vol 32, iss 9 Human Genome Genetics Generic health relevance Antarctic Regions Arctic Regions Base Sequence Chlorophyta Genes Plant Genetic Speciation Introns Inverted Repeat Sequences Molecular Sequence Data Phylogeography Phytoplankton RNA Ribosomal 18S Sequence Analysis marine algae polar systems repetitive introns Introner Elements Biochemistry and Cell Biology Evolutionary Biology article 2015 ftcdlib 2023-08-21T18:06:53Z Spliceosomal introns are a hallmark of eukaryotic genes that are hypothesized to play important roles in genome evolution but have poorly understood origins. Although most introns lack sequence homology to each other, new families of spliceosomal introns that are repeated hundreds of times in individual genomes have recently been discovered in a few organisms. The prevalence and conservation of these introner elements (IEs) or introner-like elements in other taxa, as well as their evolutionary relationships to regular spliceosomal introns, are still unknown. Here, we systematically investigate introns in the widespread marine green alga Micromonas and report new families of IEs, numerous intron presence-absence polymorphisms, and potential intron insertion hot-spots. The new families enabled identification of conserved IE secondary structure features and establishment of a novel general model for repetitive intron proliferation across genomes. Despite shared secondary structure, the IE families from each Micromonas lineage bear no obvious sequence similarity to those in the other lineages, suggesting that their appearance is intimately linked with the process of speciation. Two of the new IE families come from an Arctic culture (Micromonas Clade E2) isolated from a polar region where abundance of this alga is increasing due to climate induced changes. The same two families were detected in metagenomic data from Antarctica--a system where Micromonas has never before been reported. Strikingly high identity between the Arctic isolate and Antarctic coding sequences that flank the IEs suggests connectivity between populations in the two polar systems that we postulate occurs through deep-sea currents. Recovery of Clade E2 sequences in North Atlantic Deep Waters beneath the Gulf Stream supports this hypothesis. Our research illuminates the dynamic relationships between an unusual class of repetitive introns, genome evolution, speciation, and global distribution of this sentinel marine alga. Article in Journal/Newspaper Antarc* Antarctic Antarctica Arctic North Atlantic Phytoplankton University of California: eScholarship Antarctic Arctic |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Human Genome Genetics Generic health relevance Antarctic Regions Arctic Regions Base Sequence Chlorophyta Genes Plant Genetic Speciation Introns Inverted Repeat Sequences Molecular Sequence Data Phylogeography Phytoplankton RNA Ribosomal 18S Sequence Analysis marine algae polar systems repetitive introns Introner Elements Biochemistry and Cell Biology Evolutionary Biology |
spellingShingle |
Human Genome Genetics Generic health relevance Antarctic Regions Arctic Regions Base Sequence Chlorophyta Genes Plant Genetic Speciation Introns Inverted Repeat Sequences Molecular Sequence Data Phylogeography Phytoplankton RNA Ribosomal 18S Sequence Analysis marine algae polar systems repetitive introns Introner Elements Biochemistry and Cell Biology Evolutionary Biology Simmons, Melinda P Bachy, Charles Sudek, Sebastian van Baren, Marijke J Sudek, Lisa Ares, Manuel Worden, Alexandra Z Intron Invasions Trace Algal Speciation and Reveal Nearly Identical Arctic and Antarctic Micromonas Populations |
topic_facet |
Human Genome Genetics Generic health relevance Antarctic Regions Arctic Regions Base Sequence Chlorophyta Genes Plant Genetic Speciation Introns Inverted Repeat Sequences Molecular Sequence Data Phylogeography Phytoplankton RNA Ribosomal 18S Sequence Analysis marine algae polar systems repetitive introns Introner Elements Biochemistry and Cell Biology Evolutionary Biology |
description |
Spliceosomal introns are a hallmark of eukaryotic genes that are hypothesized to play important roles in genome evolution but have poorly understood origins. Although most introns lack sequence homology to each other, new families of spliceosomal introns that are repeated hundreds of times in individual genomes have recently been discovered in a few organisms. The prevalence and conservation of these introner elements (IEs) or introner-like elements in other taxa, as well as their evolutionary relationships to regular spliceosomal introns, are still unknown. Here, we systematically investigate introns in the widespread marine green alga Micromonas and report new families of IEs, numerous intron presence-absence polymorphisms, and potential intron insertion hot-spots. The new families enabled identification of conserved IE secondary structure features and establishment of a novel general model for repetitive intron proliferation across genomes. Despite shared secondary structure, the IE families from each Micromonas lineage bear no obvious sequence similarity to those in the other lineages, suggesting that their appearance is intimately linked with the process of speciation. Two of the new IE families come from an Arctic culture (Micromonas Clade E2) isolated from a polar region where abundance of this alga is increasing due to climate induced changes. The same two families were detected in metagenomic data from Antarctica--a system where Micromonas has never before been reported. Strikingly high identity between the Arctic isolate and Antarctic coding sequences that flank the IEs suggests connectivity between populations in the two polar systems that we postulate occurs through deep-sea currents. Recovery of Clade E2 sequences in North Atlantic Deep Waters beneath the Gulf Stream supports this hypothesis. Our research illuminates the dynamic relationships between an unusual class of repetitive introns, genome evolution, speciation, and global distribution of this sentinel marine alga. |
format |
Article in Journal/Newspaper |
author |
Simmons, Melinda P Bachy, Charles Sudek, Sebastian van Baren, Marijke J Sudek, Lisa Ares, Manuel Worden, Alexandra Z |
author_facet |
Simmons, Melinda P Bachy, Charles Sudek, Sebastian van Baren, Marijke J Sudek, Lisa Ares, Manuel Worden, Alexandra Z |
author_sort |
Simmons, Melinda P |
title |
Intron Invasions Trace Algal Speciation and Reveal Nearly Identical Arctic and Antarctic Micromonas Populations |
title_short |
Intron Invasions Trace Algal Speciation and Reveal Nearly Identical Arctic and Antarctic Micromonas Populations |
title_full |
Intron Invasions Trace Algal Speciation and Reveal Nearly Identical Arctic and Antarctic Micromonas Populations |
title_fullStr |
Intron Invasions Trace Algal Speciation and Reveal Nearly Identical Arctic and Antarctic Micromonas Populations |
title_full_unstemmed |
Intron Invasions Trace Algal Speciation and Reveal Nearly Identical Arctic and Antarctic Micromonas Populations |
title_sort |
intron invasions trace algal speciation and reveal nearly identical arctic and antarctic micromonas populations |
publisher |
eScholarship, University of California |
publishDate |
2015 |
url |
https://escholarship.org/uc/item/77k998gg |
op_coverage |
2219 - 2235 |
geographic |
Antarctic Arctic |
geographic_facet |
Antarctic Arctic |
genre |
Antarc* Antarctic Antarctica Arctic North Atlantic Phytoplankton |
genre_facet |
Antarc* Antarctic Antarctica Arctic North Atlantic Phytoplankton |
op_source |
Molecular Biology and Evolution, vol 32, iss 9 |
op_relation |
qt77k998gg https://escholarship.org/uc/item/77k998gg |
op_rights |
public |
_version_ |
1776202460637954048 |