A Study of the Heterochromatin of<i>Asellus Aquaticus</i>(Crust. Isop.)

Rocchi, A.; Prantera, Giorgio; Castro, M. Di

doi:10.1080/00087114.1980.10796853

Cited by 19 publications

(7 citation statements)

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“…The same staining properties are also shown by two interstitial heterochromatic regions located on a probable Y chromosome undergoing morphological differentiation, which is present in part of the males of a natural population (Rocchi et al 1980(Rocchi et al , 1984.…”

Section: Discussionsupporting

confidence: 50%

“…The telomeric regions of the same chromosomes usually stain differentially after Cbanding, fluoresce brightly after staining with chromomycin A3 (CMA) and remain dark after staining with quinacrine mustard, thus demonstrating that they contain constitutive heterochromatin rich in GC bases. These areas display a high degree of polymorphism, involving not only their number but also their size (Rocchi et al 1980). Rocchi et al (1980Rocchi et al ( , 1984 found that some males of a Sarno River population had two interstitial heterochromatic areas on one of the chromosomes of a pair that possessed the same staining properties as telomeric heterochromatin.…”

Section: Introductionmentioning

confidence: 98%

“…These areas display a high degree of polymorphism, involving not only their number but also their size (Rocchi et al 1980). Rocchi et al (1980Rocchi et al ( , 1984 found that some males of a Sarno River population had two interstitial heterochromatic areas on one of the chromosomes of a pair that possessed the same staining properties as telomeric heterochromatin. This chromosome is inherited through the male line as a normal Y chromosome and probably represents an early stage of morphological differentiation of a sex chromosome.…”

Section: Introductionmentioning

confidence: 98%

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Heterochromatin and ribosomal genes inAsellus aquaticus (Crust. Isop.)

1996

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In the present investigation chromosomal preparations of Asellus aquaticus were sequentially stained with chromomycin A3 to reveal the heterochromatic areas, hybridized in situ with rDNA probes in order to map the ribosomal genes and finally silver stained to check the transcriptional activity of these genes. The results indicate the existence of a substantial correspondence of location and size among the heterochromatic regions and the regions over which the in situ hybridization signals spread. The ribosomal genes, quite independently of their location in the secondary constriction, can be silver stained and thus appear to be transcriptionally active. The ribosomal sequences also hybridize to the entire heterochromatic areas observed on the probable Y chromosome identified in some males of a natural population. These rRNA genes are only rarely transcriptionally active.

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Section: Discussionsupporting

confidence: 50%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 98%

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Heterochromatin and ribosomal genes inAsellus aquaticus (Crust. Isop.)

1996

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“…A heteromorphic chromosome pair has recently been identified in a certain number of males in a wild population collected in the Sarno river near Naples. This heteromorphism was detected by C-banding and consists of the presence of two heterochromatin areas on a metacentric chromosome, located one on each arm in an interstitial position (heterochromosome) (Rocchi et a!., 1980). The heterochromosome is inherited only by the male offspring of males which have it.…”

Section: Introductionmentioning

confidence: 99%

Morphological differentiation of a sex chromosome and ribosomal genes in Asellus aquaticus (Crust. Isop.)

et al. 1992

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The karyotype of the isopod crustacean Asellus aquaticus does not normally display any\ud heteromorphic sex chromosome pair. Some of the males in a wild population of A. aquaticus\ud collected in the Sarno river near Naples do display a heteromorphic chromosome pair. The heteromorphism\ud is due to the presence of two intercalary heterochromatic areas on one chromosome.\ud This chromosome is inherited through the male line as a normal Y chromosome. The heteromorphic\ud pair has retained the capacity to recombine during meiosis. In-situ hybridization of ribosomal\ud probes, labelled with digoxigenin—dUTP, reveals that ribosomal sequences are associated\ud with both intercalary heterochromatic areas of the heterochromosome. The ribosomal genes are\ud normally telomeric and associated with heterochromatin. After digestion of genomic DNA with\ud BamHI, EcoRl and HindIII restriction endonucleases and hybridization with ribosomal probes, the\ud hybridization patterns of the males with the heterochromosome differ from those of the males without\ud the heterochromosome, as well as from those of the females, which are identical. The possible\ud origin of the morphological differentiation of the heterochromosome, and the causes of the differences\ud in the ribosomal DNA restriction patterns linked to the presence of this chromosome, are discussed

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“…The characteristics of the heterochromatin of P. coxa/is described above (i.e. stainability with chromomycin Ah telomeric location and numerical and size polymorphism) are shared with A. aquaticus (RoccHI et al 1980 The genome size of the two species is also different and A. aquaticus contains about 3 times more DNA than P. coxalis (VALENTINO et al 1983). …”

Section: Resultsmentioning

confidence: 99%