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...
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| Format: | Article |
| Language: | English |
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Wiley
2020-01-01
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| Series: | International Journal of Genomics |
| Online Access: | http://dx.doi.org/10.1155/2020/6540343 |
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| 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 |
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