A Milia

Major and 5S ribosomal sequences of the largemouth bass Micropterus salmoides (Perciformes, Centrarchidae) are localized in GC-rich regions of the genome

Major and 5S ribosomal genes have been localized in the chromosomes of Micropterus salmoides. By C-banding, Ag-staining, CMA3-staining and 45S and 5S fluorescence in-situ hybridization (FISH), we demonstrate that the 45S and 5S ribosomal genes are clustered in two different chromosome pairs and both are located in heterochromatic GC-rich regions. PCR amplification and sequencing of the 5S intergenic non-transcribed sequences have allowed us to identify variability essentially due to a trinucleotide tandem repeat (GCT).

A further case of a 22;22 Robertsonian translocation associated with recurrent abortions

SummaryA case of 22;22 Robertsonian translocation, identified in the husband of a woman who had five early abortions, is reported.

Karyotype, C- and G-banding, and nucleolar organizer regions of Conger conger (Osteichthyes, Anguilliformes)

Abstract The diploid chromosome number of Conger conger L. was found to be 2n = 38, with the karyotype consisting of four pairs of metacentric, two of submetacentric and thirteen of acrocentric chromosomes. C‐ and G‐banding allowed the identification of homologous chromosomes. NOR was identified on the short arm of the smallest acrocentric pair.

Ring chromosome 14 mosaicism: an unusual case associated with developmental delay and epilepsy, characterized by genome array-CGH.

Ring Chromosome 14 Mosaicism: An Unusual Case Associated With Developmental Delay and Epilepsy, Characterized by Genome Array-CGH Anna Lisa Nucaro,* Melania Falchi, Tiziana Pisano, Rossano Rossino, Francesca Boscarelli, Giusi Stoico, Angela Milia, Caterina Montaldo, Carlo Cianchetti, and Dario Pruna INN-CNR, Cittadella Universitaria, Monserrato, Cagliari, Italy Clinica di Neuropsichiatria Infantile, Azienda Ospedaliero-Universitaria, Cagliari, Italy Dipartimento di Scienze Pediatriche e Medicina Clinica, Azienda Ospedaliero-Universitaria, Cagliari, Italy Dipartimento di Scienze Chirurgiche e Odontostomatologiche, Universit a di Cagliari, Cagliari, Italy Technogenetics Bouty, Company, Sesto San Giovanni, Italy Dipartimento di Biologia Sperimentale, Universit a di Cagliari, Cagliari, Italy

A case of D13 ring chromosome.

SummaryA case of D ring chromosome identified with trypsin banding as a 13 with loss of the bands p12 and q34 is reported. The clinical features characteristically associated with the loss of these specific segments were present.

Mitotic and meiotic chromosomes of the American lobster Homarus americanus (Nephropidae, Decapoda)

The chromosomes of H. americanus have been characterised by C-banding, fluorochrome banding and restriction endonuclease banding. Thanks to these techniques, it has been possible to identify mitotic and meiotic figures clearly and to study the distribution and structure of heterochromatic regions. Moreover, we have identified small supernumerary chromosomes, variable in number and often asynaptic in first meiotic metaphase.

CYTOGENETIC AND MOLECULAR CHARACTERISTICS OF ATLANTIC EELS (ANGUILLA ANGUILLA AND A. ROSTRATA) GENOME

Abstract The Atlantic eels, Anguilla anguilla and A. rostrata, have partially overlapping spawning sites and show incomplete reproductive isolation as testified by the presence of hybrids at low frequency. Nevertheless, significant genetic differences between the two species have been pointed out by data on biochemical polymorphisms and mitochondrial DNA. This study reviews the cyto‐genetic and molecular data and points out differences and similarities between the two species.

Heterochromatin distribution and structure in Gymnothorax unicolor (Anguilliformes, Muraenidae)

Abstract Mitotic chromosomes of the moray eel, Gymnothorax unicolor, were digested in situ with Alul, Haelll, Mbol and Ddel restriction endonucleases, and the results were compared with those obtained in the other Mediterranean species of the same family, Muraena helena. Thanks to restriction endonuclease‐ (RE‐) banding technique, it is possible to study the distribution and structure of heterochromatic regions, since subsets of constitutive heterochromatin sensitive/resistant to nuclease action can be observed. From an analysis of the banding patterns it was possible to study the karyotypic structural changes between the two species.

Ring 20 syndrome mosaicism and epilepsy: a case with duplication of two BAC clones in 20q11.21-q11.22 defined by genome array-CGH

Herein, we report an unusual case of ring 20 mosaicism in a 15-year-old non-dysmorphic girl with epilepsy refractory to drug therapy. Ring 20 syndrome is a rare condition still not well characterised both at the genetic and clinical levels. It was described for the first time by Borgaonkar and Bolling1 as a genetic syndrome. To date, about 60 mostly sporadic cases of patients have been reported with de novo ring formation. This syndrome is characterised by a large degree of phenotypic variability, in association with a characteristic form of epilepsy, refractory to any pharmacological therapy with non-convulsive status epilepticus and cognitive problems. The first seizures occur in the first years of life and represent the first clinical signs. Further clinical signs are mental retardation of varying degrees, and behavioural disorders. The case reported showed an unusual ring chromosome 20 mosaicism associated with epilepsy and generalised tonic clonic seizures refractory to drug therapy and behaviour disorders. Cytogenetic analysis, performed on cultured peripheral blood, revealed the presence of ring 20 mosaicism in 40% of the metaphases examined (20 out of 50). The patient, the firstborn of non-consanguineous healthy parents, was born after a normal pregnancy. The neonatal period followed a normal course, with increases in weight–height and psychomotor development. The parents reported …

Cryptic Chromosome Rearrangements in Five Patients, with Normal and/or Abnormal Karyotypes, Associated with Mental Retardation, Autism and/or Epilepsy, Detected by BAC Genome Array-CGH

This report describes the usefulness of the BAC genome array-CGH platform in the detection of cryptic rearrangements. We examined ten patients with normal and/or abnormal karyotypes and dysmorphic features, associated with mental retardation, autism and/or epilepsy. This approach led us to discover further cryptic chromosomal rearrangements, not previously detected by conventional cytogenetic procedures, and allowed us to better delineate genotype/phenotype correlation. Our experience shows the validity of the BAC platform as a reliable method for genome-wide screening of chromosomal aberrations in patient with idiopathic mental retardation and/or in association with autism and epilepsy.