The evolutionary trajectory of the mating-type (<it>mat</it>) genes in <it>Neurospora </it>relates to reproductive behavior of taxa
<p>Abstract</p> <p>Background</p> <p>Comparative sequencing studies among a wide range of taxonomic groups, including fungi, have led to the discovery that reproductive genes evolve more rapidly than other genes. However, for fungal reproductive genes the question has r...
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| Format: | Article |
| Language: | English |
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BMC
2008-04-01
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| Series: | BMC Evolutionary Biology |
| Online Access: | http://www.biomedcentral.com/1471-2148/8/109 |
| _version_ | 1818900638433542144 |
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| author | Johannesson Hanna Karlsson Magnus Wik Lotta |
| author_facet | Johannesson Hanna Karlsson Magnus Wik Lotta |
| author_sort | Johannesson Hanna |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>Comparative sequencing studies among a wide range of taxonomic groups, including fungi, have led to the discovery that reproductive genes evolve more rapidly than other genes. However, for fungal reproductive genes the question has remained whether the rapid evolution is a result of stochastic or deterministic processes. The mating-type (<it>mat</it>) genes constitute the master regulators of sexual reproduction in filamentous ascomycetes and here we present a study of the molecular evolution of the four <it>mat</it>-genes (<it>mat a-1</it>, <it>mat A-1</it>, <it>mat A-2 </it>and <it>mat A-3</it>) of 20 <it>Neurospora </it>taxa.</p> <p>Results</p> <p>We estimated nonsynonymous and synonymous substitution rates of genes to infer their evolutionary rate, and confirmed that the <it>mat</it>-genes evolve rapidly. Furthermore, the evolutionary trajectories are related to the reproductive modes of the taxa; likelihood methods revealed that positive selection acting on specific codons drives the diversity in heterothallic taxa, while among homothallic taxa the rapid evolution is due to a lack of selective constraint. The latter finding is supported by presence of stop codons and frame shift mutations disrupting the open reading frames of <it>mat a-1</it>, <it>mat A-2 </it>and <it>mat A-3 </it>in homothallic taxa. Lower selective constraints of <it>mat</it>-genes was found among homothallic than heterothallic taxa, and comparisons with non-reproductive genes argue that this disparity is not a nonspecific, genome-wide phenomenon.</p> <p>Conclusion</p> <p>Our data show that the <it>mat</it>-genes evolve rapidly in <it>Neurospora</it>. The rapid divergence is due to either adaptive evolution or lack of selective constraints, depending on the reproductive mode of the taxa. This is the first instance of positive selection acting on reproductive genes in the fungal kingdom, and illustrates how the evolutionary trajectory of reproductive genes can change after a switch in reproductive behaviour of an organism.</p> |
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| format | Article |
| id | doaj.art-16190f016f6f45afb0a404019aff7120 |
| institution | Directory Open Access Journal |
| issn | 1471-2148 |
| language | English |
| last_indexed | 2024-12-19T20:07:02Z |
| publishDate | 2008-04-01 |
| publisher | BMC |
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| series | BMC Evolutionary Biology |
| spelling | doaj.art-16190f016f6f45afb0a404019aff71202022-12-21T20:07:26ZengBMCBMC Evolutionary Biology1471-21482008-04-018110910.1186/1471-2148-8-109The evolutionary trajectory of the mating-type (<it>mat</it>) genes in <it>Neurospora </it>relates to reproductive behavior of taxaJohannesson HannaKarlsson MagnusWik Lotta<p>Abstract</p> <p>Background</p> <p>Comparative sequencing studies among a wide range of taxonomic groups, including fungi, have led to the discovery that reproductive genes evolve more rapidly than other genes. However, for fungal reproductive genes the question has remained whether the rapid evolution is a result of stochastic or deterministic processes. The mating-type (<it>mat</it>) genes constitute the master regulators of sexual reproduction in filamentous ascomycetes and here we present a study of the molecular evolution of the four <it>mat</it>-genes (<it>mat a-1</it>, <it>mat A-1</it>, <it>mat A-2 </it>and <it>mat A-3</it>) of 20 <it>Neurospora </it>taxa.</p> <p>Results</p> <p>We estimated nonsynonymous and synonymous substitution rates of genes to infer their evolutionary rate, and confirmed that the <it>mat</it>-genes evolve rapidly. Furthermore, the evolutionary trajectories are related to the reproductive modes of the taxa; likelihood methods revealed that positive selection acting on specific codons drives the diversity in heterothallic taxa, while among homothallic taxa the rapid evolution is due to a lack of selective constraint. The latter finding is supported by presence of stop codons and frame shift mutations disrupting the open reading frames of <it>mat a-1</it>, <it>mat A-2 </it>and <it>mat A-3 </it>in homothallic taxa. Lower selective constraints of <it>mat</it>-genes was found among homothallic than heterothallic taxa, and comparisons with non-reproductive genes argue that this disparity is not a nonspecific, genome-wide phenomenon.</p> <p>Conclusion</p> <p>Our data show that the <it>mat</it>-genes evolve rapidly in <it>Neurospora</it>. The rapid divergence is due to either adaptive evolution or lack of selective constraints, depending on the reproductive mode of the taxa. This is the first instance of positive selection acting on reproductive genes in the fungal kingdom, and illustrates how the evolutionary trajectory of reproductive genes can change after a switch in reproductive behaviour of an organism.</p>http://www.biomedcentral.com/1471-2148/8/109 |
| spellingShingle | Johannesson Hanna Karlsson Magnus Wik Lotta The evolutionary trajectory of the mating-type (<it>mat</it>) genes in <it>Neurospora </it>relates to reproductive behavior of taxa BMC Evolutionary Biology |
| title | The evolutionary trajectory of the mating-type (<it>mat</it>) genes in <it>Neurospora </it>relates to reproductive behavior of taxa |
| title_full | The evolutionary trajectory of the mating-type (<it>mat</it>) genes in <it>Neurospora </it>relates to reproductive behavior of taxa |
| title_fullStr | The evolutionary trajectory of the mating-type (<it>mat</it>) genes in <it>Neurospora </it>relates to reproductive behavior of taxa |
| title_full_unstemmed | The evolutionary trajectory of the mating-type (<it>mat</it>) genes in <it>Neurospora </it>relates to reproductive behavior of taxa |
| title_short | The evolutionary trajectory of the mating-type (<it>mat</it>) genes in <it>Neurospora </it>relates to reproductive behavior of taxa |
| title_sort | evolutionary trajectory of the mating type it mat it genes in it neurospora it relates to reproductive behavior of taxa |
| url | http://www.biomedcentral.com/1471-2148/8/109 |
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