Duplication of distal 20q: clinical, cytogenetic and array CGH. Characterization of a new case.

Trisomy of the long arm of chromosome 20 is rare. We describe an 18-month-old male who was born at 36 weeks via Caesarian section after an uneventful pregnancy. During the newborn period he was found to have a right-sided cleft lip and cleft palate, hypertelorism, strabismus and mildly over-folded ears with cupping. Cardiovascular examination was consistent with the diagnosis of severe aortic coarctation, which was confirmed by echocardiogram. Additionally, hypothyroidism was diagnosed. Neurological evaluation at 18 months revealed a hypotonic infant with delayed acquisition of motor milestones. Cytogenetic analysis showed additional material on the long arm of chromosome 20, confirmed by fluorescence in situ hybridization (FISH) analysis as being of chromosome 20 origin. Because of the indistinct GTG-banding pattern it was not possible to distinguish between a proximal [dup(20)(q11.2q13.1)] or distal duplication [dup(20)(q13.1q13.3)]. To further define the duplication we used array comparative genomic hybridization (CGH) which demonstrated a 7.8 Mb interstitial duplication in distal 20q. Thus, the proband's karyotype was interpreted as 46,XY,dup(20)(q13.2q13.2). The proband is the first reported case of a pure duplication of this region. This case further highlights the utility of array CGH in characterizing aneusomies and, in particular, for accurate breakpoint designation and quantitation of ambiguous rearrangements.

[Inducing chromosome translocation and deletions by Chinese Spring-Agilops 2C disomic addition x Chinese Spring-Elytriga 5E disomic addition].

Crossing between two disomic addition lines, Chinese Spring-E. elongata and Chinese Sping with two gametocidal chromosomes 2C (from Ae. cylindric), was carried out to investigate the function of gametocidal chromosome. After scrutinizing the meiosis of pollen mother cells (PMCs) in F1 hybrids, several results were concluded: (1) In seven of the crossing combinations, the number of univalents exceeded the expected and some trivalents and tetravalents appeared also in MI; lagging, breakage and bridge of chromosomes were observed in anaphase and telophase; considerable micronuclei formed in telophase and tetrads. These were mainly caused by the gametocidal chromosome 2C. (2) Chromosomes 6E and 7E were more susceptible to the effect of the gametocidal chromosome 2C. (3) The gametocidal chromosome 2C functioned in prophase viz. the period of forming synaptonemal complex. Four F1 lines, 5-14, 5-37, 5-67 and 5-71, were identified to be T5ES 4AST5EL 2BS, T5EL 3AS, T5ES 5BS translocation respectively by using C-banding and genome in situ hybrydization(GISH) analysis. Deletion was detected in line 5-17 (short arm of chromosome 2A), 5-27(6B), 5-18(4B and 5B), 5-72(4A) and 5-4(4B) by C-banding analysis. The statistic data showed that gametocidal chromosome could induce translocation with a high frequency of 5% and reacted on group B more efficiently than on groups A and D since translocation involving chromosome 4A, 2B, 3A, 5B and deletion involving chromosome 6B, 5B, 4B, 4A 2A according to Endo's work.

[Chromosome CPD(PI/DAPI)- and CMA/DAPI-banding patterns in Allium cepa L]. / SPD/(PI/DAPI)- i SMA/DAPI-differentsial'naia ischerchennost' khromosom Allium cepa L.

Chromosome banding patterns of Allium cepa L. were obtained by using fluorochrome combinations chromomycin A3 (CMA) + 4',6-diamidino-2-phenylindole (DAPI), DAPI + actinomycin D (AMD) and propidium iodide (PI) + DAPI. In A. cepa, telomeric heterochromatin displayed dull fluorescence after staining with DAPI and DAPI/AMD. After staining with the GC-specific CMA and AT-specific DAPI, the CMA-positive fluorescence of the NOR region and the telomeric bands of C-heterochromatin was observed. In combination with DAPI, PI, a dye with low AT/GC specificity, produced almost uniform fluorescence of chromosomal arms and heterochromatin, whereas the NOR-adjoining regions displayed bright fluorescence. Denaturation of chromosomal DNA (95 degrees C for 1-3 min) followed by renaturation in the 2 x SSC buffer (37 degrees C, 12 h) altered the chromosome fluorescence patterns: specific PI-positive bands appeared and the contrast of CMA-banding increased. Bright fluorescence of the NOR and adjoining regions was also observed in the case. Three-minute denaturation led also to a bright PI-positive fluorescence of telomeric heterochromatin. The denaturation of chromosomal DNA before staining results in changes of the DAPI fluorescence pattern and in the appearance of DAPI fluorescence in GR-rich NOP regions. The mechanisms underlying the effects of denaturation/renaturation procedures on chromosome banding patterns obtained with different fluorochromes are discussed.

Bandeo de cromosomas humanos con extracto crudo de frutas u hojas de papaya / Human chromosome banding with raw extract of fruits or leaves of papaya

One week old human chromosome preparations were treated with filtrate from one liquefied leaf (53 g) of papaya (Carica papaya) in 100 ml of distilled water, and stained with 1.5 Giemsa (pH 6.8). Good chromosome banding was obtained after 2 min of treatment. Solutions that have been frozen even for years are effective and the method is cheaper and easier than others.

[Human chromosome banding with raw extract of fruits or leaves of papaya]. / Bandeo de cromosomas humanos con extracto crudo de frutas u hojas de papaya.

One week old human chromosome preparations were treated with filtrate from one liquefied leaf (53 g) of papaya (Carica papaya) in 100 ml of distilled water, and stained with 1.5% Giemsa (pH 6.8). Good chromosome banding was obtained after 2 min of treatment. Solutions that have been frozen even for years are effective and the method is cheaper and easier than others.

Bivariate flow karyotyping in broad bean (Vicia faba).

In the present study, we report on the development of bivariate flow karyotyping in the legume broad bean (Vicia faba). We optimised chromosome staining with 4',6-diamidino-2-phenylindole and mithramycin A and analysed chromosome suspensions prepared from a line with standard (wild-type) karyotype and from six translocation lines with reconstructed karyotypes. Chromosomes were isolated from formaldehyde-fixed root tips after cell cycle synchronisation, and their fluorescence was analysed with dual-laser flow cytometry after the staining. High-resolution bivariate flow karyotypes were obtained in all broad bean lines analysed. Compared with univariate analysis, the bivariate analysis permitted discrimination of more chromosome types. However, peaks corresponding to newly resolved chromosomes were rather closely spaced, which could have compromised the purity of sorted fractions. With only a few exceptions, chromosome peaks were in a straight line, suggesting only minor differences in the AT:GC ratio among the chromosomes. These results indicate the limited potential of bivariate flow cytometric analysis and sorting in broad bean.