Localization of the repetitive telomeric sequence (TTAGGG)n in four salmonid species

Genome ◽  
1996 ◽  
Vol 39 (5) ◽  
pp. 1035-1038 ◽  
Author(s):  
M. Abuín ◽  
P. Martínez ◽  
L. Sánchez

We have analyzed the localization of the highly conserved telomeric sequence (TTAGGG)n in four salmonid species, two of the genus Salmo (Salmo trutta and Salmo salar) and two of the genus Oncorhynchus (Onchorhynchus mykiss and Onchorhynchus kisutch), by fluorescent in situ hybridization. As expected, the hybridization signal was mostly localized at the telomeres of all chromosomes in the four species. Two species evidenced special hybridization sites with the telomeric probe: (i) interstitial heterochromatic blocks in particular long chromosomes in S. salar, this observation supports tandem fusions as the karyotypic evolutionary mechanism leading to the formation of the long acrocentric and submetacentric chromosomes in the karyotype of S. salar; (ii) the whole NOR region in O. mykiss; this observation suggests that the (TTAGGG)n sequence is scattered all along this chromosome region. Key words : Salmo, Oncorhynchus, telomeres, in situ hybridization, evolution.

Genome ◽  
2000 ◽  
Vol 43 (1) ◽  
pp. 185-190 ◽  
Author(s):  
J Perez ◽  
P Moran ◽  
E Garcia-Vazquez

This work describes the isolation, characterization, and physical location of the methionine tRNA in the genome of Atlantic salmon (Salmo salar L.) and brown trout (Salmo trutta L.). An Atlantic salmon genomic library was screened using a tRNAMet probe from Xenopus laevis. Two cosmid clones containing the Atlantic salmon tRNAMet gene were isolated, subcloned and sequenced. The tRNAMet was mapped to metaphase chromosomes by fluorescence in situ hybridization (FISH). Chromosomal data indicated that the tDNA of methionine is tandemly repeated in a single locus in both species. Analysis of genomic DNA by Southern hybridization confirmed the tandem organization of this gene. Key words: cosmids, cloning, in situ hybridization, tRNAMet.


Genome ◽  
2004 ◽  
Vol 47 (4) ◽  
pp. 742-746 ◽  
Author(s):  
Francesco Fontana ◽  
Ronald M Bruch ◽  
Fred P Binkowski ◽  
Massimo Lanfredi ◽  
Milvia Chicca ◽  
...  

A karyotype analysis using several staining techniques was carried out on the North American lake sturgeon, Acipenser fulvescens. The chromosome number was found to be 2n = 262 ± 6. A representative karyotype of 264 chromosomes was composed of 134 meta- and submetacentrics, 70 telo- and acrocentrics, and 60 microchromosomes. The constitutive heterochromatin, revealed by C banding, was localized in various positions on several chromosomes, including microchromosomes. The signals of fluorescent in situ hybridization (FISH) with a HindIII satellite DNA probe were visible as centromeric heterochromatin blocks on 48 chromosomes. The telomeric repeat (TTAGGG)n detected by FISH was localized at both ends of all chromosomes and two chromosomes were entirely marked. Fluorescent staining with GC-specific chromomycin A3 showed recognizable fluorescent regions, whereas a more uniform base composition was revealed by the AT-specific 4',6-diamidino-2-phenylindole (DAPI). After silver staining, the active nucleolar organizer regions (NORs) were detected on 12 chromosomes. FISH with the 5S probe showed four signals on four small chromosomes. Our data suggest that A. fulvescens is a tetraploid species.Key words: karyotype, C banding, telomeric sequence, fluorochrome staining, satellite DNA, 5S rDNA.


1993 ◽  
Vol 63 (3) ◽  
pp. 192-193 ◽  
Author(s):  
L.D. McDaniel ◽  
W.J. Lederer ◽  
P. Kofuji ◽  
D.H. Schulze ◽  
R. Kieval ◽  
...  

2007 ◽  
Vol 177 (4S) ◽  
pp. 596-597
Author(s):  
Joseph P. Alukal ◽  
Bobby B. Najari ◽  
Wilson Chuang ◽  
Lata Murthy ◽  
Monica Lopez-Perdomo ◽  
...  

2021 ◽  
pp. 112067212110307
Author(s):  
Raquel María Moral ◽  
Carlos Monteagudo ◽  
Javier Muriel ◽  
Lucía Moreno ◽  
Ana María Peiró

Introduction: Conjunctival melanoma is extremely rare in children and has low rates of resolution. Definitive histopathological diagnosis based exclusively on microscopic findings is sometimes difficult. Thus, early diagnosis and adequate treatment are essential to improve clinical outcomes. Clinical case: We present the first case in which the fluorescent in situ hybridization (FISH) diagnostic technique was applied to a 10-year-old boy initially suspected of having amelanotic nevi in his right eye. Based on the 65% of tumor cells with 11q13 (CCND1) copy number gain and 33% with 6p25 (RREB1) gain as measured by the FISH analysis, and on supporting histopathological findings, the diagnosis of conjunctival melanoma could be made. Following a larger re-excision, adjuvant therapy with Mitomycin C (MMC), cryotherapy and an amniotic membrane graft, the patient has remained disease-free during 9 years of long-term follow-up. Case discussion: Every ophthalmologist should remember to consider and not forget the possibility of using FISH analyses during the differential diagnosis of any suspicious conjunctival lesions. Genetic techniques, such as FISH, have led to great advances in the classification of ambiguous lesions. Evidence-based guidelines for diagnosing conjunctival melanoma in the pediatric population are needed to determine the most appropriate strategy for this age group.


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