Molecular evolution in Panagrolaimusnematodes: origins of parthenogenesis, hermaphroditism and the Antarctic species P. davidi
Abstract Background As exemplified by the famously successful model organism Caenorhabditis elegans , nematodes offer outstanding animal systems for investigating diverse biological phenomena due to their small genome sizes, short generation times and ease of laboratory maintenance. Nematodes in the...
Main Authors: | , , , , , , |
---|---|
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
BioMed Central Ltd.
2009
|
Subjects: | |
Online Access: | http://www.biomedcentral.com/1471-2148/9/15 |
id |
ftbiomed:oai:biomedcentral.com:1471-2148-9-15 |
---|---|
record_format |
openpolar |
spelling |
ftbiomed:oai:biomedcentral.com:1471-2148-9-15 2023-05-15T13:58:52+02:00 Molecular evolution in Panagrolaimusnematodes: origins of parthenogenesis, hermaphroditism and the Antarctic species P. davidi Lewis, Samantha C Dyal, Leslie A Hilburn, Caroline F Weitz, Stephanie Liau, Wei-Siang LaMunyon, Craig W Denver, Dee R 2009-01-16 http://www.biomedcentral.com/1471-2148/9/15 en eng BioMed Central Ltd. http://www.biomedcentral.com/1471-2148/9/15 Copyright 2009 Lewis et al; licensee BioMed Central Ltd. Research article 2009 ftbiomed 2009-04-02T19:37:07Z Abstract Background As exemplified by the famously successful model organism Caenorhabditis elegans , nematodes offer outstanding animal systems for investigating diverse biological phenomena due to their small genome sizes, short generation times and ease of laboratory maintenance. Nematodes in the genus Panagrolaimus have served in comparative development and anhydrobiosis studies, and the Antarctic species P. davidi offers a powerful paradigm for understanding the biological mechanisms of extreme cold tolerance. Panagrolaimus nematodes are also unique in that examples of gonochoristic, hermaphroditic and parthenogenetic reproductive modes have been reported for members of this genus. The evolutionary origins of these varying reproductive modes and the Antarctic species P. davidi , however, remain enigmatic. Results We collected nuclear ribosomal RNA gene and mitochondrial protein-coding gene sequences from diverse Panagrolaimus species and strains, including newly discovered isolates from Oregon, to investigate phylogenetic relationships in this nematode genus. Nuclear phylogenies showed that the species and strains historically identified as members of Panagrolaimus constitute a paraphyletic group, suggesting that taxonomic revision is required for Panagrolaimus and related nematode lineages. Strain-specific reproductive modes were mapped onto the molecular phylogeny to show a single origin of parthenogenesis from a presumably gonochoristic ancestor. The hermaphroditic strains were all placed outside a major monophyletic clade that contained the majority of other Panagrolaimus nematodes. Phylogenetic analyses of mitochondrial sequences showed that substantial molecular and geographic diversity exists within the clade of parthenogenetic strains. The Antarctic species P. davidi was found to be very closely related to two Panagrolaimus strains from southern California. Phylogenetic and molecular clock analyses suggested that P. davidi and the California strain PS1579 shared a common ancestor in the very recent evolutionary past. Conclusion Our study provides a phylogenetic framework for understanding the evolutionary origins and diversification patterns of varying reproductive modes within Panagrolaimus and important insights into the origin of the Antarctic species P. davidi . Panagrolaimus offers a powerful nematode model for understanding diverse evolutionary phenomena including the evolution of asexuality and the adaptive evolution of extreme cold tolerance. Article in Journal/Newspaper Antarc* Antarctic BioMed Central Antarctic The Antarctic |
institution |
Open Polar |
collection |
BioMed Central |
op_collection_id |
ftbiomed |
language |
English |
description |
Abstract Background As exemplified by the famously successful model organism Caenorhabditis elegans , nematodes offer outstanding animal systems for investigating diverse biological phenomena due to their small genome sizes, short generation times and ease of laboratory maintenance. Nematodes in the genus Panagrolaimus have served in comparative development and anhydrobiosis studies, and the Antarctic species P. davidi offers a powerful paradigm for understanding the biological mechanisms of extreme cold tolerance. Panagrolaimus nematodes are also unique in that examples of gonochoristic, hermaphroditic and parthenogenetic reproductive modes have been reported for members of this genus. The evolutionary origins of these varying reproductive modes and the Antarctic species P. davidi , however, remain enigmatic. Results We collected nuclear ribosomal RNA gene and mitochondrial protein-coding gene sequences from diverse Panagrolaimus species and strains, including newly discovered isolates from Oregon, to investigate phylogenetic relationships in this nematode genus. Nuclear phylogenies showed that the species and strains historically identified as members of Panagrolaimus constitute a paraphyletic group, suggesting that taxonomic revision is required for Panagrolaimus and related nematode lineages. Strain-specific reproductive modes were mapped onto the molecular phylogeny to show a single origin of parthenogenesis from a presumably gonochoristic ancestor. The hermaphroditic strains were all placed outside a major monophyletic clade that contained the majority of other Panagrolaimus nematodes. Phylogenetic analyses of mitochondrial sequences showed that substantial molecular and geographic diversity exists within the clade of parthenogenetic strains. The Antarctic species P. davidi was found to be very closely related to two Panagrolaimus strains from southern California. Phylogenetic and molecular clock analyses suggested that P. davidi and the California strain PS1579 shared a common ancestor in the very recent evolutionary past. Conclusion Our study provides a phylogenetic framework for understanding the evolutionary origins and diversification patterns of varying reproductive modes within Panagrolaimus and important insights into the origin of the Antarctic species P. davidi . Panagrolaimus offers a powerful nematode model for understanding diverse evolutionary phenomena including the evolution of asexuality and the adaptive evolution of extreme cold tolerance. |
format |
Article in Journal/Newspaper |
author |
Lewis, Samantha C Dyal, Leslie A Hilburn, Caroline F Weitz, Stephanie Liau, Wei-Siang LaMunyon, Craig W Denver, Dee R |
spellingShingle |
Lewis, Samantha C Dyal, Leslie A Hilburn, Caroline F Weitz, Stephanie Liau, Wei-Siang LaMunyon, Craig W Denver, Dee R Molecular evolution in Panagrolaimusnematodes: origins of parthenogenesis, hermaphroditism and the Antarctic species P. davidi |
author_facet |
Lewis, Samantha C Dyal, Leslie A Hilburn, Caroline F Weitz, Stephanie Liau, Wei-Siang LaMunyon, Craig W Denver, Dee R |
author_sort |
Lewis, Samantha C |
title |
Molecular evolution in Panagrolaimusnematodes: origins of parthenogenesis, hermaphroditism and the Antarctic species P. davidi |
title_short |
Molecular evolution in Panagrolaimusnematodes: origins of parthenogenesis, hermaphroditism and the Antarctic species P. davidi |
title_full |
Molecular evolution in Panagrolaimusnematodes: origins of parthenogenesis, hermaphroditism and the Antarctic species P. davidi |
title_fullStr |
Molecular evolution in Panagrolaimusnematodes: origins of parthenogenesis, hermaphroditism and the Antarctic species P. davidi |
title_full_unstemmed |
Molecular evolution in Panagrolaimusnematodes: origins of parthenogenesis, hermaphroditism and the Antarctic species P. davidi |
title_sort |
molecular evolution in panagrolaimusnematodes: origins of parthenogenesis, hermaphroditism and the antarctic species p. davidi |
publisher |
BioMed Central Ltd. |
publishDate |
2009 |
url |
http://www.biomedcentral.com/1471-2148/9/15 |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_relation |
http://www.biomedcentral.com/1471-2148/9/15 |
op_rights |
Copyright 2009 Lewis et al; licensee BioMed Central Ltd. |
_version_ |
1766267231552929792 |