Journal ArticleDOI
Complex sex chromosome system in Eigenmannia sp. (Pisces, Gymnotiformes)
TLDR
C-banding analysis of the mitotic chromosomes revealed constitutive heterochromatin in the centromeric regions of all acrocentrics, however, small metacentrics were C-band negative.Abstract:
Chromosomes of Eigenmannia sp. (7 males and 15 females) collected from the Tiete River in Botucatu (SP, Brazil) were examined from gill, kidney and testicular cells. The diploid chromosome number in males was 2n=31 and in females, 2n=32. In both sexes the number of chromosomal arms was 40. The difference in diploid number was due to the fusion of two acrocentrics. Mitotic and meiotic studies suggested that one of the fused acrocentrics was the Y chromosome. The sex-determining mechanism in Eigenmannia sp. could therefore be XX, AA in the female and X, \-YA A in the males. One of the males presented 2n=30 chromosomes due to the occurrence of another fusion of acrocentrics. C-banding analysis of the mitotic chromosomes revealed constitutive heterochromatin in the centromeric regions of all acrocentrics. However, small metacentrics were C-band negative. The YA chromosome is C-band negative except for a small amount of heterochromatin in the centromeric region. The nucleolar organizer region as identified by Ag-staining is present in the interstitial region of chromosome pair No. 10.read more
Citations
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Journal ArticleDOI
Sex determination and sex differentiation in fish: an overview of genetic, physiological, and environmental influences
TL;DR: The lability of sex-determination systems in fish makes some species sensitive to environmental pollutants capable of mimicking or disrupting sex hormone actions, and such observations provide important insight into potential impacts from endocrine disruptors, and can provide useful monitoring tools for impacts on aquatic environments.
Journal ArticleDOI
Turnover of Sex Chromosomes in the Stickleback Fishes (Gasterosteidae)
Joseph A. Ross,Joseph A. Ross,James R. Urton,James R. Urton,Jessica Boland,Michael D. Shapiro,Catherine L. Peichel +6 more
TL;DR: The sex-chromosome diversity that is uncovered in sticklebacks provides a rich comparative resource for understanding the mechanisms that underlie the rapid turnover of sex- Chromosome systems.
Journal ArticleDOI
Chromosome banding in Amphibia. XXVIII. Homomorphic XY sex chromosomes and a derived Y-autosome translocation in Eleutherodactylus riveroi (Anura, Leptodactylidae).
TL;DR: Extensive cytogenetic analyses on a population of the leptodactylid frog Eleutherodactylus riveroi in northern Venezuela revealed the existence of multiple XXAA♂/XYAA♀/XAAY as discussed by the authors.
Journal ArticleDOI
Turnover of sex chromosomes and speciation in fishes
Jun Kitano,Catherine L. Peichel +1 more
TL;DR: It is demonstrated that the neo-X chromosome (X2) plays an important role in phenotypic divergence and reproductive isolation between these sympatric sticklebacks, as well as recent advances in understanding of the evolutionary role of sex chromosome turnover in stickleback speciation.
Journal ArticleDOI
Distribution of sex chromosome mechanisms in neotropical fish and description of a ZZ/ZW system in Parodon hilarii (Parodontidae)
TL;DR: A review of the sex chromosome of neotropical fish is presented and some aspects of their differentiation are discussed, with emphasis on the family Parodontidae.
References
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Journal ArticleDOI
Controlled silver-staining of nucleolus organizer regions with a protective colloidal developer: a 1-step method.
W. M. Howell,Deborah Black +1 more
TL;DR: A 1-step silver-staining technique, requiring only 2 min to perform, is described for the differential staining of nucleolus organizer regions.
Journal Article
Cytotaxonomic considerations on Hoplias Lacerdae (Pisces, Erythrinidae)
Journal ArticleDOI
Rapid Chromosome Preparations from Solid Tissues of Fishes
TL;DR: A technique is described for obtaining well-spread metaphases from solid tissues of fishes without the use of methodologies that rely on tissue grinders, centrifuges, digestive enzymes, or tissue culture.
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Controlled silver-staining of nucleolus organizer regions with a protective colloidal developer: a 1-step method.
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