Chromosome

About: Chromosome is a research topic. Over the lifetime, 17538 publications have been published within this topic receiving 660077 citations. The topic is also known as: chromosomes & GO:0005694.

The possibility of latent centromeres and a proposed nomenclature system for total chromosome and whole arm translocations

Abstract: Translocations involving entire chromosomes or whole chromosome arms may not necessarily require deletion of a centromere. Conceivably, in the process of centromeric or telomeric fusion or of fusion of a centromere with a telomere, centromeric inactivation may occur, thus preserving both centromeres—one functional, the other latent—in the resultant translocation chromosome. If such latent centromeres exist and, in addition, are capable of being reactivated, it would explain how additional functional centromeres are acquired in the reverse process of chromosomal fission or fragmentation. A system of nomenclature is proposed for identifying the origin and nature of these chromosomal rearrangements.

Chromosome-sized DNA molecules of Plasmodium falciparum

Abstract: At least seven chromosome-sized DNA molecules (750 to 2000 kilobases in length and one fraction of undetermined molecular weight) from cultured clones and isolates of Plasmodium falciparum have been separated by pulsed-field gradient gel electrophoresis Whereas asexual blood stages and sexual stages of the same line have identical molecular karyotypes, the length of chromosome-sized DNA molecules among different geographical isolates and several clones derived from a single patient is different These length alterations of chromosomes are the result of DNA rearrangements that must occur unrelated to sexual differentiation

Frequency and distribution of chromosome abnormalities in human oocytes

Abstract: It was previously shown that more than half of the human oocytes obtained from IVF patients of advanced reproductive age are aneuploid, due to meiosis I and meiosis II errors. The present paper furthe

Non-invasive prenatal testing of fetal whole chromosome aneuploidy by massively parallel sequencing.

Abstract: Objective To determine whether non-invasive prenatal testing by maternal plasma DNA sequencing can uncover all fetal chromosome aneuploidies in one simple sequencing event. Methods Plasma samples from 435 pregnant women at high risk for Down syndrome were collected prior to amniocentesis in three hospitals in China between March 2009 and June 2011. We sequenced the plasma DNA extracted from these samples at low coverage. We discovered that the genome representation of each of the 24 chromosomes obeyed a linear relationship to its GC content. Applying this relationship, we analysed the copy number of each of the 24 chromosomes. Full fetal karyotyping was compared with maternal plasma DNA sequencing results. Results Among the 435 samples, 412 samples (94.7%) have full karyotyping and sequencing results. Sixty-seven samples containing a fetal chromosome aneuploidy, including trisomy 21, trisomy 18, trisomy 13, trisomy 9, monosomy X or others, can be accurately identified with a detection sensitivity of 100% and a detection specificity of 99.71%. Normalization of the chromosome representation values against chromosomal guanine/cytosine base content is the key issue to ensure the accuracy. Conclusions Our results indicate that non-invasive detection of fetal chromosome aneuploidies for all 24 chromosomes in one single sequencing event is feasible. © 2013 John Wiley & Sons, Ltd.

Cytological and molecular characterization of oat x maize partial hybrids.

Abstract: In cereals, interspecific and intergeneric hybridizations (wide crosses) which yield karyotypically stable hybrid plants have been used as starting points to widen the genetic base of a crop and to construct stocks for genetic analysis. Also, uniparental genome elimination in karyotypically unstable hybrids has been utilized for cereal haploid production. We have crossed hexaploid oat (2n=6x=42, Avena sativa L.) and maize (2n=2x=20, Zea mays L.) and recovered 90 progenies through embryo rescue. Fifty-two plants (58%) produced from oatxmaize hybridization were oat haploids (2n=3x=21) following maize chromosome elimination. Twenty-eight plants (31%) were found to be stable partial hybrids with 1-4 maize chromosomes in addition to a haploid set of 21 oat chromosomes (2n=21+1 to 2n=21+4). Ten of the ninety plants produced were found to be apparent chromosomal chimeras, where some tissues in a given plant contained maize chromosomes while other tissues did not, or else different tissues contained a different number of maize chromosomes. DNA restriction fragment length polymorphisms (RFLPs) were used to identify the maize chromosome(s) present in the various oat-maize progenies. Maize chromosomes 2, 3, 4, 5, 6, 7, 8, and 9 were detected in partial hybrids and chromosomal chimeras. Maize chromosomes 1 and 10 were not detected in the plants analyzed to-date. Furthermore, partial self-fertility, which is common in oat haploids, was also observed in some oat-maize hybrids. Upon selfing, partial hybrids with one or two maize chromosomes showed nearly complete transmission of the maize chromosome to give self-fertile maize-chromosome-addition oat plants. Fertile lines were recovered that contained an added maize chromosome or chromosome pair representing six of the ten maize chromosomes. Four independently derived disomic maize chromosome addition lines contained chromosome 4, one line carried chromosome 7, two lines had chromosome 9, one had chromosome 2, and one had chromosome 3. One maize chromosome-8 monosomic addition line was also identified. We also identified a double disomic addition line containing both maize chromosomes 4 and 7. This constitutes the first report of the production of karyotypically stable partial hybrids involving highly unrelated species from two subfamilies of the Gramineae (Pooideae - oat, and Panicoideae - maize) and the subsequent recovery of fertile oat-maize chromosome addition lines. These represent novel material for gene/ marker mapping, maize chromosome manipulation, the study of maize gene expression in oat, and the transfer of maize DNA, genes, or active transposons to oat.