Exceptional Enlargement of the Mitochondrial Genome Results from Distinct Causes in Different Rain Frogs (Anura: Brevicipitidae: Breviceps)

The mitochondrial (mt) genome of the bushveld rain frog (Breviceps adspersus, Brevicipitidae, Afrobatrachia) is the largest (28.8 kbp) among the vertebrates investigated to date. The major cause of genome size enlargement in this species is the duplication of multiple genomic regions. To investigate...

Full description

Saved in:
Bibliographic Details
Main Authors: Keitaro Hemmi, Ryosuke Kakehashi, Chiaki Kambayashi, Louis Du Preez, Leslie Minter, Nobuaki Furuno, Atsushi Kurabayashi
Format: Article
Language:English
Published: Wiley 2020-01-01
Series:International Journal of Genomics
Online Access:http://dx.doi.org/10.1155/2020/6540343
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1832559254854172672
author Keitaro Hemmi
Ryosuke Kakehashi
Chiaki Kambayashi
Louis Du Preez
Leslie Minter
Nobuaki Furuno
Atsushi Kurabayashi
author_facet Keitaro Hemmi
Ryosuke Kakehashi
Chiaki Kambayashi
Louis Du Preez
Leslie Minter
Nobuaki Furuno
Atsushi Kurabayashi
author_sort Keitaro Hemmi
collection DOAJ
description The mitochondrial (mt) genome of the bushveld rain frog (Breviceps adspersus, Brevicipitidae, Afrobatrachia) is the largest (28.8 kbp) among the vertebrates investigated to date. The major cause of genome size enlargement in this species is the duplication of multiple genomic regions. To investigate the evolutionary lineage, timing, and process of mt genome enlargement, we sequenced the complete mtDNAs of two congeneric rain frogs, B. mossambicus and B. poweri. The mt genomic organization, gene content, and gene arrangements of these two rain frogs are very similar to each other but differ from those of B. adspersus. The B. mossambicus mt genome (22.5 kbp) does not differ significantly from that of most other afrobatrachians. In contrast, the B. poweri mtDNA (28.1 kbp) is considerably larger: currently the second largest among vertebrates, after B. adspersus. The main causes of genome enlargement differ among Breviceps species. Unusual elongation (12.5 kbp) of the control region (CR), a single major noncoding region of the vertebrate mt genome, is responsible for the extremely large mt genome in B. poweri. Based on the current Breviceps phylogeny and estimated divergence age, it can be concluded that the genome enlargements occurred independently in each species lineage within relatively short periods. Furthermore, a high nucleotide substitution rate and relaxation of selective pressures, which are considered to be involved in changes in genome size, were also detected in afrobatrachian lineages. Our results suggest that these factors were not direct causes but may have indirectly affected mt genome enlargements in Breviceps.
format Article
id doaj-art-ff54876640874df2a67a9a94764b0274
institution Kabale University
issn 2314-436X
2314-4378
language English
publishDate 2020-01-01
publisher Wiley
record_format Article
series International Journal of Genomics
spelling doaj-art-ff54876640874df2a67a9a94764b02742025-02-03T01:30:30ZengWileyInternational Journal of Genomics2314-436X2314-43782020-01-01202010.1155/2020/65403436540343Exceptional Enlargement of the Mitochondrial Genome Results from Distinct Causes in Different Rain Frogs (Anura: Brevicipitidae: Breviceps)Keitaro Hemmi0Ryosuke Kakehashi1Chiaki Kambayashi2Louis Du Preez3Leslie Minter4Nobuaki Furuno5Atsushi Kurabayashi6Amphibian Research Center, Hiroshima University, Hiroshima 739-8526, JapanAmphibian Research Center, Hiroshima University, Hiroshima 739-8526, JapanAmphibian Research Center, Hiroshima University, Hiroshima 739-8526, JapanUnit for Environmental Sciences and Management, North-West University, Potchefstroom 2520, South AfricaUnit for Environmental Sciences and Management, North-West University, Potchefstroom 2520, South AfricaAmphibian Research Center, Hiroshima University, Hiroshima 739-8526, JapanAmphibian Research Center, Hiroshima University, Hiroshima 739-8526, JapanThe mitochondrial (mt) genome of the bushveld rain frog (Breviceps adspersus, Brevicipitidae, Afrobatrachia) is the largest (28.8 kbp) among the vertebrates investigated to date. The major cause of genome size enlargement in this species is the duplication of multiple genomic regions. To investigate the evolutionary lineage, timing, and process of mt genome enlargement, we sequenced the complete mtDNAs of two congeneric rain frogs, B. mossambicus and B. poweri. The mt genomic organization, gene content, and gene arrangements of these two rain frogs are very similar to each other but differ from those of B. adspersus. The B. mossambicus mt genome (22.5 kbp) does not differ significantly from that of most other afrobatrachians. In contrast, the B. poweri mtDNA (28.1 kbp) is considerably larger: currently the second largest among vertebrates, after B. adspersus. The main causes of genome enlargement differ among Breviceps species. Unusual elongation (12.5 kbp) of the control region (CR), a single major noncoding region of the vertebrate mt genome, is responsible for the extremely large mt genome in B. poweri. Based on the current Breviceps phylogeny and estimated divergence age, it can be concluded that the genome enlargements occurred independently in each species lineage within relatively short periods. Furthermore, a high nucleotide substitution rate and relaxation of selective pressures, which are considered to be involved in changes in genome size, were also detected in afrobatrachian lineages. Our results suggest that these factors were not direct causes but may have indirectly affected mt genome enlargements in Breviceps.http://dx.doi.org/10.1155/2020/6540343
spellingShingle Keitaro Hemmi
Ryosuke Kakehashi
Chiaki Kambayashi
Louis Du Preez
Leslie Minter
Nobuaki Furuno
Atsushi Kurabayashi
Exceptional Enlargement of the Mitochondrial Genome Results from Distinct Causes in Different Rain Frogs (Anura: Brevicipitidae: Breviceps)
International Journal of Genomics
title Exceptional Enlargement of the Mitochondrial Genome Results from Distinct Causes in Different Rain Frogs (Anura: Brevicipitidae: Breviceps)
title_full Exceptional Enlargement of the Mitochondrial Genome Results from Distinct Causes in Different Rain Frogs (Anura: Brevicipitidae: Breviceps)
title_fullStr Exceptional Enlargement of the Mitochondrial Genome Results from Distinct Causes in Different Rain Frogs (Anura: Brevicipitidae: Breviceps)
title_full_unstemmed Exceptional Enlargement of the Mitochondrial Genome Results from Distinct Causes in Different Rain Frogs (Anura: Brevicipitidae: Breviceps)
title_short Exceptional Enlargement of the Mitochondrial Genome Results from Distinct Causes in Different Rain Frogs (Anura: Brevicipitidae: Breviceps)
title_sort exceptional enlargement of the mitochondrial genome results from distinct causes in different rain frogs anura brevicipitidae breviceps
url http://dx.doi.org/10.1155/2020/6540343
work_keys_str_mv AT keitarohemmi exceptionalenlargementofthemitochondrialgenomeresultsfromdistinctcausesindifferentrainfrogsanurabrevicipitidaebreviceps
AT ryosukekakehashi exceptionalenlargementofthemitochondrialgenomeresultsfromdistinctcausesindifferentrainfrogsanurabrevicipitidaebreviceps
AT chiakikambayashi exceptionalenlargementofthemitochondrialgenomeresultsfromdistinctcausesindifferentrainfrogsanurabrevicipitidaebreviceps
AT louisdupreez exceptionalenlargementofthemitochondrialgenomeresultsfromdistinctcausesindifferentrainfrogsanurabrevicipitidaebreviceps
AT leslieminter exceptionalenlargementofthemitochondrialgenomeresultsfromdistinctcausesindifferentrainfrogsanurabrevicipitidaebreviceps
AT nobuakifuruno exceptionalenlargementofthemitochondrialgenomeresultsfromdistinctcausesindifferentrainfrogsanurabrevicipitidaebreviceps
AT atsushikurabayashi exceptionalenlargementofthemitochondrialgenomeresultsfromdistinctcausesindifferentrainfrogsanurabrevicipitidaebreviceps