Karyotype supporting &lt;i&gt;Mugil curema&lt;/i&gt; Valenciennes, 1836 and &lt;i&gt;Mugil gaimardianus&lt;/i&gt; Desmarest, 1831 (Mugilidae: Teleostei) as two valid nominal species

Nirchio, Mauro; Cervigón, Fernando; Porto, Jorge Ivan Rebelo; Pérez, Julio E.; Gómez, José Jorge Aranda; Villalaz, Janzel

doi:10.3989/scimar.2003.67n1113

Cited by 27 publications

(33 citation statements)

References 6 publications

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“…Specifically considering mullet in the area, through different mtDNA markers (Fraga et al, 2007;Heras et al, 2009;BOLD), at least three different clusters can be identified within M. curema, which also include other mullet species. Similarly, in the same species complex, from a cytogenetic point of view, in addition to the two cytotypes described above, it has to be mentioned the chromosome complement of M. rubrioculus, formerly considered M. curema ( Nirchio et al, 2003Nirchio et al, , 2007, which has allowed to confirm it as a valid species. As one M. curema population from Brazil (Nirchio et al, 2005) exhibits a chromosome complement with 2n=28 (Cytotype 1) apparently similar to the one described for M. incilis from Brazil (Pauls et al, 1998;Galetti et al, 2000;Netto et al, 2007), further sampling of Brazilian specimens is necessary to check out whether or not they belong to a different species from M. curema.…”

Section: Discussionmentioning

confidence: 94%

“…The peculiar cytotaxonomic features of Mugil incilis might constitute a clear cut diagnostic tool in showing species boundaries, which might be very helpful in identifying cryptic species in the M. curema complex, as already occurred (Nirchio et al, 2003; on the other hand, present data indicates that it would be useful to add cytogenetic data on the other Mugilidae species which have yet to be described and to parallely increase the molecular database on them, in order to clarify the karyoevolutive patterns and the phylogenetic relationships within the family.…”

Section: Discussionmentioning

confidence: 97%

“…Recent cytogenetic studies carried out on several Mugilidae species from Venezuela (reviewed in Sola et al, 2007Sola et al, , 2008 have provided information regarding several interesting systematic and cytotaxonomic issues within the family. For example, the cytogenetic studies made it possible to establish that Mugil rubrioculus is a separate species from M. curema (Nirchio et al, 2003 and also indicated the likely existence of a species complex within M. curema (Nirchio & Cequea, 1998;Nirchio et al, 2005a). Moreover, the localization of major and minor ribosomal genes revealed that the 48 uniarmed chromosome karyotype, displayed by all the Mugilidae species, with the exception of M. curema, is much more differentiated than the macromorphology of chromosomes would suggest (Sola et al, , 2008.…”

Section: Introductionmentioning

confidence: 99%

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Karyotype characterization of Mugil incilis Hancock, 1830 (Mugiliformes: Mugilidae), including a description of an unusual co-localization of major and minor ribosomal genes in the family

et al. 2011

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This study reports the description of the karyotype of Mugil incilis from Venezuela. The chromosome complement is composed of 48 acrocentric chromosomes, which uniformly decrease in size. Therefore, the homologues can not be clearly identified, with the exception of one of the largest chromosome pairs, classified as number 1, whose homologues may show a subcentromeric secondary constriction, and of chromosome pair number 24, which is considerably smaller than the others. C-banding showed heterochromatic blocks at the centromeric/pericentromeric regions of all chromosomes, which were more conspicuous on chromosomes 1, given the C-positive signals include the secondary constrictions. AgNO 3 and fluorescent in situ hybridization (FISH) with 45S rDNA demonstrated that the nucleolus organizer regions are indeed located on the secondary constrictions of chromosome pair number 1. FISH with 5S rDNA revealed that the minor ribosomal genes are located on this same chromosome pair, near the NORs, though signals are closer to the centromeres and of smaller size, compared to those of the major ribosomal gene clusters. This is the first description of co-localization of major and minor ribosomal genes in the family. Data are discussed from a cytotaxonomic and phylogenetic perspective.Se presenta la primera descripción del cariotipo de Mugil incilis de Venezuela. El complemento cromosómico está compuesto por 48 cromosomas acrocéntricos uniformemente decrecientes en tamaño. Por lo tanto, los homólogos no pueden ser claramente identificados, con excepción de uno de los pares de mayor tamaño, clasificado como número 1, cuyos homólogos poseen una constricción secundaria subcentromérica, y el par de cromosomas número 24, considerablemente más pequeño que los otros. El bandeo-C reveló bloques heterocromáticos en las regiones centroméricas/pericentroméricas de todos los cromosomas, más conspicuas en el cromosoma 1 en el que las señales C-positivas se encuentra localizada precisamente en la constricción secundaria. La tinción con AgNO 3 y la Hibridación Fluorescente in situ (FISH) con sonda 45S rDNA revelaron que las regiones organizadoras del nucléolo están ciertamente localizadas sobre la constricción secundaria del cromosoma número 1. FISH con 5S rDNA reveló que los genes ribosomales menores están ubicados en este mismo par cromosómico, en posición proximal a las NORs, aunque cercanas al centrómero y de menor tamaño en comparación con los clúster de genes ribosomales mayores. Ésta es la primera descripción de co-localización de genes ribosomales mayores y menores en la familia Mugilidae. Los datos se discuten bajo perspectivas citotaxonómicas y filogenéticas.

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Section: Discussionmentioning

confidence: 94%

Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Karyotype characterization of Mugil incilis Hancock, 1830 (Mugiliformes: Mugilidae), including a description of an unusual co-localization of major and minor ribosomal genes in the family

et al. 2011

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“…Moreover, Mugil sp. (formerly gaimardianus, suppressed name by the International Commission on Zoological Nomenclature, ICZN 1787) and M. curema were recently identified as separate species on the basis of their karyotype (Nirchio et al, 2003), which reveals the importance of karyotypic studies in solving taxonomic problems among closely related species.…”

Section: Introductionmentioning

confidence: 99%

Cytogenetical and morphological features reveal significant differences among Venezuelan and Brazilian samples of Mugil curema (Teleostei: Mugilidae)

et al. 2005

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Karyotype of M. curema from the Gulf of Mexico and Brazil have been reported as possessing chromosome complement with 2n=28 and FN=48, whereas specimens from Venezuela has been reported as possessing a diploid number 2n=24 and a conserved FN (48). Although at first sight this variation suggests the presence of a chromosomal intraspecific (interpopulational) variability, the possibility that we are dealing with two different species was examined. This work revisit the karyotypes of M. curema from Venezuela and Brazil, including new data on C-banding, and NOR localization, and compares morphologic characteristics of samples from both localities. Thus, besides diploid number, the constitutive heterochromatin distribution and NORs location, mark other differences between M. curema Cytotype 1 (2n=28; FN=48) and Cytotype 2 (2n=24; NF=48). Moreover, morphologic comparison revealed differences in the scale counts and pectoral fin rays: 35 scales in the middle body line and 15 pectoral fin rays in specimens possessing the karyotype 2n=28, compared with 37-39 scales in the middle body line and 17 pectoral fin rays in specimens with the karyotype 2n=24. These differences lead us to suggest that both cytotypes are not related merely to geographic polytipic variations but could correspond to different species.Os cariótipos de M. curema do Golfo do México e do Brasil possuem 2n=28 cromossomos e NF=48. Espécimes da Venezuela, entretanto, apresentam um número diplóide de 28 cromossomos e um NF conservado (48). Apesar desta variação sugerir, a princípio, uma variabilidade intraespecífica (interpopulacional), a possibilidade de estarmos perante diferentes espécies foi investigada. O presente trabalho re-analisa os cariótipos de M. curema da Venezuela e do Brasil, incluindo novos dados sobre bandamento C e localização das NORs e compara caracteres merísticos e morfométricos de amostras de ambas as localidades. Assim, junto com o número cromossômico, a heterocromatina constitutiva e a distribuição das NORs trazem outras diferenças entre M. curema Citótipo 1 (2n=48, FN=48) e Citótipo 2 (2n=48, FN=48). Além disso, as comparações dos caracteres morfológicos revelam diferenças nas contagens, com 35 escamas na linha média do corpo e 15 raios nas nadadeiras peitorais nos espécimes com cariótipo 2n=28, já o cariótipo 2n=24 apresenta 37-39 escamas e 17 raios nas peitorais. Essas diferenças sugerem que ambos citótipos não estão relacionados meramente a variações geográficas politípicas mas que podem corresponder a diferentes espécies.

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“…Furthermore, the FISH observations revealed very week additional signals in the interstitial position in two chromosome pairs, contrasting with the results described by Wasko, Galetti (2000) for other Brycon species. The FISH technique using 18S rDNA sequences has identifi ed a higher number of major ribosomal cistrons than the Ag-NOR technique in several species of fi sh: Salmo trutta Linnaeus, 1758 (Pendás et al, (Nirchio et al, 2003), Lebias fasciata Valenciennes, 1821 (Tigano et al, 2004) and Triportheus venezuelensis Spix, 1829 (Nirchio et al, 2007). Even though these signals may be technical artifacts, they would also represent chromosome regions with NORs that are usually unexpressed, due to DNA methylation and gene silencing related to positional effects induced by heterochromatin (C-bands) and/or telomeres, as suggested by Guillén et al (2004).…”

Section: Comp Cytogenet 2010 4(2)mentioning

confidence: 99%

Cytogenetic characterization of Brycon amazonicus (Spix et Agassiz, 1829) (Teleostei: Characidae) from Caicara del Orinoco, Venezuela

Mariguela¹,

Nirchio²,

Ron³

et al. 2010

CCG

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Abstract.A cytogenetic analysis by conventional Giemsa staining, silver staining, C-banding, and fl uorescence in situ hybridization (FISH) was carried out on Brycon amazonicus from Caicara del Orinoco, Venezuela. The karyotype of this species is characterized by the presence of 2n = 50 chromosomes, a karyotypic formula 22m+14sm+14st, and a fundamental number of 100 chromosomal arms. Nucleolar organizer regions (NORs) and 18S rDNA genes are located in the terminal regions of the long arms of the second pair of subtelocentric chromosomes, corresponding to pair 13. C-banding revealed heterochromatin distribution in only seven chromosome pairs. The largest metacentric pair (number 1) possesses a paracentromeric block equilocally distributed in both chromosome arms, whereas in pairs 12 to 17 positive C band blocks were located in the paracentromeric region of the long arm, close to the centromere. Analysis performed with 5S rDNA gene revealed a terminal site located on the short arm of one small submetacentric chromosome (pair 15) corroborating previous studies with this repetitive gene showing an apparent conservation of 5S rDNA in the genome of these fi sh species. The data obtained in this study reinforce the chromosomal conservativeness in the species of the genus Brycon, related not only to the macro-chromosomal structure (diploid number, karyotypic formula, and fundamental number), but also to the repeated DNAs, such as heterochromatic regions and ribosomal DNAs. These data will contribute to a better understanding of chromosomal evolution in both Brycon and Characidae fi shes.

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Karyotype supporting <i>Mugil curema</i> Valenciennes, 1836 and <i>Mugil gaimardianus</i> Desmarest, 1831 (Mugilidae: Teleostei) as two valid nominal species

Cited by 27 publications

References 6 publications

Karyotype characterization of Mugil incilis Hancock, 1830 (Mugiliformes: Mugilidae), including a description of an unusual co-localization of major and minor ribosomal genes in the family

Karyotype characterization of Mugil incilis Hancock, 1830 (Mugiliformes: Mugilidae), including a description of an unusual co-localization of major and minor ribosomal genes in the family

Cytogenetical and morphological features reveal significant differences among Venezuelan and Brazilian samples of Mugil curema (Teleostei: Mugilidae)

Cytogenetic characterization of Brycon amazonicus (Spix et Agassiz, 1829) (Teleostei: Characidae) from Caicara del Orinoco, Venezuela

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