Unusually short tandem repeats in the chromosome end structure of Rhynchosciara (Diptera: Sciaridae)

• Published in: Genetica Vol. 131; no. 2; pp. 109 - 116
• Main Authors: Rossato, Renata M, Madalena, Christiane R. G, Gorab, Eduardo
• Format: Journal Article
• Language: English
• Published: Netherlands Dordrecht : Springer Netherlands 01.10.2007; Springer Nature B.V
• Subjects: Animals; Base Sequence; Chromosomes; Diptera; Diptera - genetics; DNA, Satellite - metabolism; Microsatellite Repeats; Molecular Sequence Data; Polymerase Chain Reaction; Repetitive Sequences, Nucleic Acid; Rhynchosciara; Salmonidae; satellites; Sciaridae; Sequence Analysis, DNA; Simple repeats; Sub-telomeres; telomeres
• ISSN: 0016-6707; 1573-6857
• DOI: 10.1007/s10709-006-9120-7

The characterisation of chromosome end (terminal and sub-terminal) sequences of Rhynchosciara americana chromosomes was continued with the screening of a plasmid library made of amplified DNA fragments from a microdissected chromosome tip. An insert chosen for analysis hybridised to two chromosome ends and contains two microsatellite arrays in close vicinity to a sequence (named M-47), part of which is significantly similar to minisatellites of Salmonidae that are frequently present in the vicinity of microsatellite arrays. PCR results using a single primer representative of M-47 elements suggest that they are also repetitive in Rhynchosciara genomes. In addition, total single primer PCR products hybridised to the non-telocentric end subset of R. americana chromosomes. Another plasmid microlibrary made of chromosome tips amplified by a single M-47 primer was screened for repeats of Rhynchosciara chromosomes. Selected inserts that hybridised strongly to non-telocentric ends of R. americana and R. hollaenderi have a tandem array of 22 bp repeats (M-22). There is sequence divergence among M-22 repeats but their mean similarity is significantly high in relation to the M-22 consensus sequence derived from the cloned tandem array. M-22 elements lie distal to the 414 bp sub-telomeric satellite array characterised previously as suggested by double labelling for M-22 hybridisation and reverse transcriptase. M-47 elements, formerly identified in Salmonidae, thus contribute to specify unusually short repeats composing the sub-telomeric structure of two Rhynchosciara species.