Chromosome banding in Amphibia. XV. Two types of Y chromosomes and heterochromatin hypervariabilty inGastrotheca pseustes (Anura, Hylidae)

Schmid, Michael; Steinlein, Claus; Friedl, Richard; Almeida, C. G. de; Haaf, Thomas; Hillis, David M.; Duellman, William E.

doi:10.1007/bf01726693

Cited by 48 publications

(50 citation statements)

References 24 publications

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“…This constriction correspond to the NOR-bearing region of this chromosome pair in both species. In addition to the marked similarity between the chromosomal morphologies of the E. guentheri and E. parvus karyotypes, the same NOR location may also denote a very close relationship between the species, as proposed by Schmid (1982) and Schmid et al (1990). The NOR heteromorphism seen in some individuals of both species apparently involved a tandem duplication of the NOR since two distinct blocks were observed with FISH and silver staining.…”

Section: Eleutherodactylus Binotatussupporting

confidence: 65%

“…The NOR heteromorphism seen in some individuals of both species apparently involved a tandem duplication of the NOR since two distinct blocks were observed with FISH and silver staining. As stated by Schmid (1982) and Schmid et al (1990), unequal meiotic crossing-over and sister chromatid exchanges could give rise to heteromorphic NOR, including duplications and deletions.…”

Section: Eleutherodactylus Binotatusmentioning

confidence: 89%

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Cytogenetics of three Brazilian species of Eleutherodactylus (Anura, Leptodactylidae) with 22 chromosomes and re-analysis of multiple translocations in E. binotatus

2004

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In this paper, we provide a cytogenetic analysis of Eleutherodactylus guentheri, E. parvus and E. binotatus. All of the species had a diploid chromosomal number of 2n = 22. The karyotypes of E. guentheri and E. parvus were very similar and differed only slightly in the morphology of pair 2. These two species also had an NOR-bearing secondary constriction on the long arms of pair 6. The karyotype of E. binotatus differed from those of E. guentheri and E. parvus in the morphology and size of the chromosomes, in the number of chromosomal arms, in the NOR location (detected on the short arms of pair 1), and in the pattern of heterochromatin. These results reinforce the differences between E. guentheri and E. binotatus and support the existence of two species group. Five individuals of E. binotatus showed morphs for pairs 2 and 3. These morphs probably arose from the translocation of a segment from one chromosome of pair 3 to a homologue of pair 2. In addition, some mitotic metaphases of E. binotatus showed spontaneous chromosomal breaks which suggested that there were sites of fragility. Meiotic diakinesis showed multiple chromosomal rings, indicating the occurrence of multiple translocations, as previously reported by other investigators. These data suggest that, in addition to fission and fusion, other chromosomal rearrangements were probably involved in the differentiation of the karyotypes of these species of Eleutherodactylus, especially E. binotatus.

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Section: Eleutherodactylus Binotatussupporting

confidence: 65%

Section: Eleutherodactylus Binotatusmentioning

confidence: 89%

Cytogenetics of three Brazilian species of Eleutherodactylus (Anura, Leptodactylidae) with 22 chromosomes and re-analysis of multiple translocations in E. binotatus

2004

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“…The three southern forms all exhibit XX/XY chromosomes, but two of them have homomorphic X and Y with distinct centromeric indexes [6]. Within the same population of marsupial frogs (Gastrotheca pseustes) there are two distinct male genotypes, with distinct telomeric regions in the long arms of the Y chromosome [7]. In males of Rana narina, two heteromorphic pairs of chromosomes (pairs 1 and 8) seem to exist [8].…”

Section: Genotypic Sex Determination (Gsd) Diversitymentioning

confidence: 99%

Sex determination: the amphibian models

2004

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-We review and discuss current knowledge about sex determination in amphibians. The astonishing wide variety of mechanisms of genotypic sex determination is presented and discussed in an evolutionary context. We recall the natural occurrence of transitory juvenile hermaphroditism in some species. Our present knowledge of the mechanisms of sex determination in amphibians is compared to that in mammals. The influence of epigenetic factors, and especially temperature is highlighted. In amphibians, the influence of temperature on sexual differentiation, that can prevail over genotypic sex determination, remains poorly considered in publications. We suggest that studies on genetic and epigenetic factors of gonadal sex differentiation in amphibians could provide substantial information on the evolutionary process of sex determination mechanisms in current living vertebrates.sex determination mechanisms / sexual differentiation / hermaphroditism / epigenetic factors

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“…Using Feulgen cytophotometry, Goin and Goin (1968) found a nuclear DNA content of 7.30 pg in cells of an unclassified Gastrotheca species. DNA flow cytometry revealed nuclear DNA amounts of 7.07 pg for G. pseustes, 8.47 for G. riobambae (Schmid et al, 1990a), and 10.90 pg for G. walkeri (Schmid et al, 2002). The mean genome sizes of the 28 males and 17 females of G. espeletia is 6.78 pg and 7.55 pg DNA, respectively.…”

Section: Genome Sizesmentioning

confidence: 99%

Chromosome banding in Amphibia

Schmid

Ziegler²,

Steinlein³

et al. 2002

Cytogenet Genome Res

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The mitotic chromosomes of an Ecuadorian population of the marsupial frog Gastrotheca espeletia were analyzed by means of banding techniques and fluorescence in situ hybridization. This species is characterized by unusual supernumerary (B) chromosomes. The maximum number of B chromosomes is 9 and they occur in three different morphological types. Banding analyses show that the B chromosomes are completely heterochromatic, consist of AT base pair-rich repeated DNA sequences, replicate their DNA in very late S-phase of the cell cycle, and are probably derived from a centromeric or paracentromeric region of a standard (A) chromosome. Exceptionally, the B chromosomes carry 18S + 28S ribosomal RNA genes and the conserved vertebrate telomeric DNA sequence appears to be underrepresented. Flow cytometric measurements of the nuclear DNA content differentiate between individuals with different numbers of B chromosomes. Significantly more B chromosomes are present in female than in male animals.

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Chromosome banding in Amphibia. XV. Two types of Y chromosomes and heterochromatin hypervariabilty inGastrotheca pseustes (Anura, Hylidae)

Cited by 48 publications

References 24 publications

Cytogenetics of three Brazilian species of Eleutherodactylus (Anura, Leptodactylidae) with 22 chromosomes and re-analysis of multiple translocations in E. binotatus

Cytogenetics of three Brazilian species of Eleutherodactylus (Anura, Leptodactylidae) with 22 chromosomes and re-analysis of multiple translocations in E. binotatus

Sex determination: the amphibian models

Chromosome banding in Amphibia

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