Publications by authors named "M Nirchio"
Article Synopsis
- Astroblepus mindoensis, an endangered Andean climbing catfish species native to Ecuador, faces challenges in species classification, prompting important taxonomic discussions.
- This study utilized an integrative approach, combining cytogenetic analysis, molecular identification, and detailed morphological measurements to enhance the understanding of the species' taxonomy.
- Findings reveal distinct chromosomal markers and an unusual sex-determination system, with further research warranted to explore these features in relation to other species in the Astroblepus genus.
Kner, 1854, is the most diverse genus among the Ancistrini (Loricariidae) with 70 valid species showing a wide geographic distribution and great taxonomic and systematic complexity. To date, about 40 taxa have been karyotyped, all from Brazil and Argentina, but the statistic is uncertain because 30 of these reports deal with samples that have not yet been identified at the species level. This study provides the first cytogenetic description of the bristlenose catfish, Rendahl, 1937, a species endemic to Ecuador, aiming to verify whether a sex chromosome system is identifiable in the species and, if so, which, and if its differentiation is associated with the presence of repetitive sequences reported for other species of the family.
View Article and Find Full Text PDFThe freshwater fish species , commonly named the Pacific fat sleeper, is an important food resource in CentralSouth America, yet almost no genetic information on it is available. A cytogenetic analysis of this species was undertaken by standard and molecular techniques (chromosomal mapping of 18S rDNA, 5S rDNA, and telomeric repeats), aiming to describe the karyotype features, verify the presence of sex chromosomes described in congeneric species, and make inferences on chromosome evolution in the genus. The karyotype (2n = 46) is mainly composed of metacentric and submetacentic chromosomes, with nucleolar organizer regions (NORs) localized on the short arms of submetacentric pair 10.
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- Lebiasinidae fishes have been largely overlooked in cytogenetic studies, which has led to a new analysis of eleven species within this family to determine their genomic characteristics.
- The research identified two main trends in chromosomal evolution: one stable condition with 36 bi-armed chromosomes in Lebiasininae, and another marked by significant chromosomal changes, particularly acrocentrization, in Pyrrhulininae.
- Additionally, the study highlights the varied distribution of ribosomal DNA among these species, indicating a general trend of 18S rDNA positioning, which may reflect an evolutionary link between Lebiasinidae and Ctenoluciidae families.
Neotropical cichlids include hundreds of species whose taxonomy has benefited of molecular phylogeny and whose karyotype evolution has been related to the amount and distribution of different classes of repetitive sequences. This study provides the first integrative molecular (cytochrome c oxidase subunit 1 and 16S sequences) and cytogenetic analyses of wild samples of the green terror , a cichlid naturally distributed in Ecuador and spread throughout the world as an aquarium pet. Molecular data revealed that sequences of green terror constitute a single monophyletic clade within the genus and allowed species attribution of uncertain samples previously cytogenetically analyzed.
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