Chromosome spreading of associated transposable elements and ribosomal DNA in the fish Erythrinus erythrinus. Implications for genome change and karyoevolution in fish
<p>Abstract</p> <p>Background</p> <p>The fish, <it>Erythrinus erythrinus</it>, shows an interpopulation diversity, with four karyomorphs differing by chromosomal number, chromosomal morphology and heteromorphic sex chromosomes. Karyomorph A has a diploid num...
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| Format: | Article |
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BMC
2010-09-01
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| Series: | BMC Evolutionary Biology |
| Online Access: | http://www.biomedcentral.com/1471-2148/10/271 |
| _version_ | 1818907434078437376 |
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| author | Cioffi Marcelo B Martins Cesar Bertollo Luiz AC |
| author_facet | Cioffi Marcelo B Martins Cesar Bertollo Luiz AC |
| author_sort | Cioffi Marcelo B |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>The fish, <it>Erythrinus erythrinus</it>, shows an interpopulation diversity, with four karyomorphs differing by chromosomal number, chromosomal morphology and heteromorphic sex chromosomes. Karyomorph A has a diploid number of 2n = 54 and does not have differentiated sex chromosomes. Karyomorph D has 2n = 52 chromosomes in females and 2n = 51 in males, and it is most likely derived from karyomorph A by the differentiation of a multiple X<sub>1</sub>X<sub>2</sub>Y sex chromosome system. In this study, we analyzed karyomorphs A and D by means of cytogenetic approaches to evaluate their evolutionary relationship.</p> <p>Results</p> <p>Conspicuous differences in the distribution of the 5S rDNA and <it>Rex3 </it>non-LTR retrotransposon were found between the two karyomorphs, while no changes in the heterochromatin and 18S rDNA patterns were found between them. <it>Rex3 </it>was interstitially dispersed in most chromosomes. It had a compartmentalized distribution in the centromeric regions of only two acrocentric chromosomes in karyomorph A. In comparison, in karyomorph D, <it>Rex3 </it>was found in 22 acrocentric chromosomes in females and 21 in males. All 5S rDNA sites co-localized with <it>Rex3</it>, suggesting that these are associated in the genome. In addition, the origin of the large metacentric Y chromosome in karyomorph D by centric fusion was highlighted by the presence of internal telomeric sites and 5S rDNA/<it>Rex3 </it>sites on this chromosome.</p> <p>Conclusion</p> <p>We demonstrated that some repetitive DNAs (5S rDNA, <it>Rex3 </it>retroelement and (TTAGGG)<sub>n </sub>telomeric repeats) were crucial for the evolutionary divergence inside <it>E. erythrinus</it>. These elements were strongly associated with the karyomorphic evolution of this species. Our results indicate that chromosomal rearrangements and genomic modifications were significant events during the course of evolution of this fish. We detected centric fusions that were associated with the differentiation of the multiple sex chromosomes in karyomorph D, as well as a surprising increase of associated 5S rDNA/<it>Rex3 </it>loci, in contrast to karyomorph A. In this sense, <it>E. erythrinus </it>emerges as an excellent model system for better understanding the evolutionary mechanisms underlying the huge genome diversity in fish. This organism can also contribute to understanding vertebrate genome evolution as a whole.</p> |
| first_indexed | 2024-12-19T21:55:03Z |
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| language | English |
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| publishDate | 2010-09-01 |
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| spelling | doaj.art-f5d6080c32ac4abd85c11f008e8b6b8d2022-12-21T20:04:18ZengBMCBMC Evolutionary Biology1471-21482010-09-0110127110.1186/1471-2148-10-271Chromosome spreading of associated transposable elements and ribosomal DNA in the fish Erythrinus erythrinus. Implications for genome change and karyoevolution in fishCioffi Marcelo BMartins CesarBertollo Luiz AC<p>Abstract</p> <p>Background</p> <p>The fish, <it>Erythrinus erythrinus</it>, shows an interpopulation diversity, with four karyomorphs differing by chromosomal number, chromosomal morphology and heteromorphic sex chromosomes. Karyomorph A has a diploid number of 2n = 54 and does not have differentiated sex chromosomes. Karyomorph D has 2n = 52 chromosomes in females and 2n = 51 in males, and it is most likely derived from karyomorph A by the differentiation of a multiple X<sub>1</sub>X<sub>2</sub>Y sex chromosome system. In this study, we analyzed karyomorphs A and D by means of cytogenetic approaches to evaluate their evolutionary relationship.</p> <p>Results</p> <p>Conspicuous differences in the distribution of the 5S rDNA and <it>Rex3 </it>non-LTR retrotransposon were found between the two karyomorphs, while no changes in the heterochromatin and 18S rDNA patterns were found between them. <it>Rex3 </it>was interstitially dispersed in most chromosomes. It had a compartmentalized distribution in the centromeric regions of only two acrocentric chromosomes in karyomorph A. In comparison, in karyomorph D, <it>Rex3 </it>was found in 22 acrocentric chromosomes in females and 21 in males. All 5S rDNA sites co-localized with <it>Rex3</it>, suggesting that these are associated in the genome. In addition, the origin of the large metacentric Y chromosome in karyomorph D by centric fusion was highlighted by the presence of internal telomeric sites and 5S rDNA/<it>Rex3 </it>sites on this chromosome.</p> <p>Conclusion</p> <p>We demonstrated that some repetitive DNAs (5S rDNA, <it>Rex3 </it>retroelement and (TTAGGG)<sub>n </sub>telomeric repeats) were crucial for the evolutionary divergence inside <it>E. erythrinus</it>. These elements were strongly associated with the karyomorphic evolution of this species. Our results indicate that chromosomal rearrangements and genomic modifications were significant events during the course of evolution of this fish. We detected centric fusions that were associated with the differentiation of the multiple sex chromosomes in karyomorph D, as well as a surprising increase of associated 5S rDNA/<it>Rex3 </it>loci, in contrast to karyomorph A. In this sense, <it>E. erythrinus </it>emerges as an excellent model system for better understanding the evolutionary mechanisms underlying the huge genome diversity in fish. This organism can also contribute to understanding vertebrate genome evolution as a whole.</p>http://www.biomedcentral.com/1471-2148/10/271 |
| spellingShingle | Cioffi Marcelo B Martins Cesar Bertollo Luiz AC Chromosome spreading of associated transposable elements and ribosomal DNA in the fish Erythrinus erythrinus. Implications for genome change and karyoevolution in fish BMC Evolutionary Biology |
| title | Chromosome spreading of associated transposable elements and ribosomal DNA in the fish Erythrinus erythrinus. Implications for genome change and karyoevolution in fish |
| title_full | Chromosome spreading of associated transposable elements and ribosomal DNA in the fish Erythrinus erythrinus. Implications for genome change and karyoevolution in fish |
| title_fullStr | Chromosome spreading of associated transposable elements and ribosomal DNA in the fish Erythrinus erythrinus. Implications for genome change and karyoevolution in fish |
| title_full_unstemmed | Chromosome spreading of associated transposable elements and ribosomal DNA in the fish Erythrinus erythrinus. Implications for genome change and karyoevolution in fish |
| title_short | Chromosome spreading of associated transposable elements and ribosomal DNA in the fish Erythrinus erythrinus. Implications for genome change and karyoevolution in fish |
| title_sort | chromosome spreading of associated transposable elements and ribosomal dna in the fish erythrinus erythrinus implications for genome change and karyoevolution in fish |
| url | http://www.biomedcentral.com/1471-2148/10/271 |
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