Wyniki wyszukiwania

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Comparative chromosomal studies in Rhinolophus formosae and R. luctus from china and Vietnam: elevation of R. l. lanosus to species rank

100%

Volleth M., So N. T., Wu Y., Li Y., Yu W., Lin L.-K., Arai S., Trifonov V., Liehr T., Harada M.

Acta Chiropterologica

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2017

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tom 19

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nr 1

For the majority of Rhinolophus species a karyotype consisting of either 58 or 62 chromosomes was reported. The members of the R. trifoliatus clade are therefore distinguished from other rhinolophids by low diploid chromosome numbers (2n) and a high rate of chromosomal changes. Recently, based on cytogenetic characters, a cryptic species, R. luctoides, was described and a subspecies, R. luctusmorio, was elevated to species rank. In the present work, the karyotypes of a male bat from Vietnam and a female one from China, both classified as R. luctus by morphological characters, were studied by G-banding and fluorescence in situ hybridization with whole chromosome painting probes derived from Aselliscus stoliczkanus. In the male specimen from Vietnam, the composition of the 15 autosomal bi-armed pairs (2n = 32, FN = 60) is identical to that of R. luctoides from Malaysia. For reason of differences in body size and baculum length as well as in skull morphology, this specimen is provisionally treated as R. cf. luctoides. The karyotype of the female specimen from Sichuan province, China, differs from R. luctoides by a whole arm reciprocal translocation resulting in an altered arm composition of pairs 3 and 4. For this reason, the elevation of the Chinese subspecies of R. luctus, i.e. R. lanosus, to species rank is suggested. The karyotype of the endemic Taiwanese species R. formosae with a diploid number of 2n = 52 is mainly composed of acrocentric autosomal pairs. Of the five bi-armed pairs, only the two smallest show the same arm composition as found in the 2n = 32 karyotypes of other members of the R. trifoliatus clade. The composition of the remaining three bi-armed pairs is unique and represents an apomorphic feature for R. formosae.

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Chromosome 5 derived small supernumerary marker: towards a genotype/phenotype correlation of proximal chromosome 5 imbalances

100%

Melo J. B., Backx L., Vermeesch J. R., Santos H. G., Sousa A. C., Kosyakova N., Weise A., von Eggeling F., Liehr T., Carreira I. M.

Journal of Applied Genetics

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2011

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tom 52

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nr 2

Small supernumerary marker chromosomes (sSMC) are a morphological heterogeneous group of additional abnormal chromosomes that cannot be characterized alone by conventional banding cytogenetics. Molecular cytogenetic techniques are valuable tools for the accurate identification of sSMC and a prerequisite for sound genetic counseling based on refined genotype/phenotype correlation. We describe a new case of a retarded patient with an sSMC derived from chromosome 5. The characterization of the sSMC was done by subcentromere-specific multicolor (subcenM) fluorescence in-situ hybridization (FISH) and by full tilling resolution array analysis, after microdissection and amplification of the marker DNA. Uniparental disomy for normal sister chromosomes of the sSMC(5) was excluded. The karyotype was mos47,XX,+r(5)(::p11.1 → q12.1::)[70%]/46,XX[30%], being the trisomic region between 46.15 ∼ 49.56 Mb and 61.25 ∼ 61.335 Mb, a region known to harbor ∼45 annotated genes. Together with a review of the previously described cases of sSMC(5) and duplications involving the 5q proximal region, we can conclude that trisomy of the 5q11 region is associated with learning difficulties and speech delay.

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How to narrow down chromosomal breakpoints in small and large derivative chromosomes – a new probe set

81%

Hamid A. B., Kreskowski K., Weise A., Kosayakova N., Mrasek K., Voigt M., Santos Guilherme R., Wagner R., Hardekopf D., Pekova S., Karamysheva T., Liehr T., Klein E.

Journal of Applied Genetics

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2012

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tom 53

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nr 3

Here a new fluorescence in situ hybridization (FISH-) based probe set is presented and its possible applications are highlighted in 34 exemplary clinical cases. The so-called pericentric-ladder-FISH (PCL-FISH) probe set enables a characterization of chromosomal breakpoints especially in small supernumerary marker chromosomes (sSMC), but can also be applied successfully in large inborn or acquired derivative chromosomes. PCL-FISH was established as 24 different chromosome-specific probe sets and can be used in two- up multicolor-FISH approaches. PCL-FISH enables the determination of a chromosomal breakpoint with a resolution between 1 and ∼10 megabasepairs and is based on locus-specific bacterial artificial chromosome (BAC) probes. Results obtained on 29 sSMC cases and five larger derivative chromosomes are presented and discussed. To confirm the reliability of PCL-FISH, eight of the 29 sSMC cases were studied by array-comparative genomic hybridization (aCGH); the used sSMC-specific DNA was obtained by glass-needle based microdissection and DOP-PCR-amplification. Overall, PCL-FISH leads to a better resolution than most FISH-banding approaches and is a good tool to narrow down chromosomal breakpoints.

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Molecular cytogenic characterization of eight small supernumerary marker chromosomes originating from chromosomes 2, 4, 8, 18, and 21 in three patients

81%

Pietrzak J., Mrasek K., Oberszyn E., Stankiewicz P., Kosyakova N., Weise A., Cheung W. W., von E. F., Mazurczak T., Bocian E., Liehr T., Cai W. W.

Journal of Applied Genetics

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2007

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tom 48

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nr 2

167-175

Small supernumerary marker chromosomes (sSMCs) are a morphologically heterogeneous group of additional structurally abnormal chromosomes that cannot be identified unambiguously by conventional banding techniques alone. Molecular cytogenetic methods enable detailed characterization of sSMCs; however, in many cases interpretation of their clinical significance is problematic. The aim of our study was to characterize precisely sSMCs identified in three patients with dysmorphic features, psychomotor retardation and multiple congenital anomalies. We also attempted to correlate the patients' genotypes with phenotypes by inclusion of data from the literature. The sSMCs were initially detected by G-banding analysis in peripheral blood lymphocytes in these patients and were subsequently characterized using multicolor fluorescence in situ hybridization (M-FISH), (sub)centromere-specific multicolor FISH (cenM-FISH, subcenM-FISH), and multicolor banding (MCB) techniques. Additionally, the sSMCs in two patients were also studied by hybridization to whole-genome bacterial artificial chromosome (BAC) arrays (array-CGH) to map the breakpoints on a single BAC clone level. In all three patients, the chromosome origin, structure, and euchromatin content of the sSMCs were determined. In patient RS, only a neocentric r(2)(q35q36) was identified. It is a second neocentric sSMC(2) in the literature and the first marker chromosome derived from the terminal part of 2q. In the other two patients, two sSMCs were found, as M-FISH detected additional sSMCs that could not be characterized in G-banding analysis. In patient MK, each of four cell lines contained der(4)(:p 11.1 →q 12:) accompanied by a sSMC( 18): r( 18)(:p 11,2→q 11.1::p 11,2→q 11.1:), inv dup( 18)(:p 11.1→ql 1.1::q 11.1→p 11.1:), or der( 18)(:p 11.2→q11.1::ql 1.1→p 11.1:). In patient NP, with clinical features of trisomy 8p, three sSMCs were characterized: r(8)(:p12→q11.1::q11.1→p21:) der(8) (:p11.22→q11.1::q11.1→p21::p21→p11.22:) and der(21)(:p11.1→q21.3:). The BAC array results confirmed the molecular cytogenetic results and refined the breakpoints to the single BAC clone resolution. However, the complex mosaic structure of the marker chromosomes derived from chromosomes 8 and 18 could only be identified by molecular cytogenetic methods. This study confirms the usefulness of multicolor FISH combined with whole-genome arrays for comprehensive analyses of marker chromosomes.

Ograniczanie wyników

Comparative chromosomal studies in Rhinolophus formosae and R. luctus from china and Vietnam: elevation of R. l. lanosus to species rank

Chromosome 5 derived small supernumerary marker: towards a genotype/phenotype correlation of proximal chromosome 5 imbalances

How to narrow down chromosomal breakpoints in small and large derivative chromosomes – a new probe set

Molecular cytogenic characterization of eight small supernumerary marker chromosomes originating from chromosomes 2, 4, 8, 18, and 21 in three patients