Biomaterial Database

Chromosome breakage and rejoining of sister chromatids in Bloom's syndrome. 1979

E Meyer-Kuhn, and E Therman

The occurrence of chromosome breaks and reunion of sister chromatids in lymphocytes of two patients with Bloom's syndrome has been compared with those found in X-rayed and control cells. The distribution of breaks in BS is non-random both between and within chromosomes, the centric regions of certain chromosomes being preferentially involved. The following working hypotheses are put forward: When chromosome breaks in human lymphocytes occur in G0-G1, practically no sister chromatid reunion (SCR) takes place, whereas ends created by an S-G2 break show a considerable tendency to SCR. We propose further that chromosome aberrations in BS mainly result from breaks in S-G2, including possible U-type rejoining of sister chromatid exchanges. Fragments extra to an intact chromosome complement result from a chromatid break or an asymmetrical chromatid translocation in a previous mitosis.

UI	MeSH Term	Description	Entries
D007621	Karyotyping	Mapping of the KARYOTYPE of a cell.	Karyotype Analysis Methods,Analysis Method, Karyotype,Analysis Methods, Karyotype,Karyotype Analysis Method,Karyotypings,Method, Karyotype Analysis,Methods, Karyotype Analysis
D008214	Lymphocytes	White blood cells formed in the body's lymphoid tissue. The nucleus is round or ovoid with coarse, irregularly clumped chromatin while the cytoplasm is typically pale blue with azurophilic (if any) granules. Most lymphocytes can be classified as either T or B (with subpopulations of each), or NATURAL KILLER CELLS.	Lymphoid Cells,Cell, Lymphoid,Cells, Lymphoid,Lymphocyte,Lymphoid Cell
D010787	Photosensitivity Disorders	Abnormal responses to sunlight or artificial light due to extreme reactivity of light-absorbing molecules in tissues. It refers almost exclusively to skin photosensitivity, including sunburn, reactions due to repeated prolonged exposure in the absence of photosensitizing factors, and reactions requiring photosensitizing factors such as photosensitizing agents and certain diseases. With restricted reference to skin tissue, it does not include photosensitivity of the eye to light, as in photophobia or photosensitive epilepsy.	Actinic Reticuloid Syndrome,Dermatitis, Actinic,Photodermatitis,Chronic Actinic Dermatitis,Photosensitization,Actinic Dermatitides,Actinic Dermatitides, Chronic,Actinic Dermatitis,Actinic Dermatitis, Chronic,Actinic Reticuloid Syndromes,Chronic Actinic Dermatitides,Dermatitides, Actinic,Dermatitides, Chronic Actinic,Dermatitis, Chronic Actinic,Disorder, Photosensitivity,Disorders, Photosensitivity,Photodermatitides,Photosensitivity Disorder,Reticuloid Syndrome, Actinic,Reticuloid Syndromes, Actinic,Syndrome, Actinic Reticuloid,Syndromes, Actinic Reticuloid
D002478	Cells, Cultured	Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.	Cultured Cells,Cell, Cultured,Cultured Cell
D002869	Chromosome Aberrations	Abnormal number or structure of chromosomes. Chromosome aberrations may result in CHROMOSOME DISORDERS.	Autosome Abnormalities,Cytogenetic Aberrations,Abnormalities, Autosome,Abnormalities, Chromosomal,Abnormalities, Chromosome,Chromosomal Aberrations,Chromosome Abnormalities,Cytogenetic Abnormalities,Aberration, Chromosomal,Aberration, Chromosome,Aberration, Cytogenetic,Aberrations, Chromosomal,Aberrations, Chromosome,Aberrations, Cytogenetic,Abnormalities, Cytogenetic,Abnormality, Autosome,Abnormality, Chromosomal,Abnormality, Chromosome,Abnormality, Cytogenetic,Autosome Abnormality,Chromosomal Aberration,Chromosomal Abnormalities,Chromosomal Abnormality,Chromosome Aberration,Chromosome Abnormality,Cytogenetic Aberration,Cytogenetic Abnormality
D003434	Crossing Over, Genetic	The reciprocal exchange of segments at corresponding positions along pairs of homologous CHROMOSOMES by symmetrical breakage and crosswise rejoining forming cross-over sites (HOLLIDAY JUNCTIONS) that are resolved during CHROMOSOME SEGREGATION. Crossing-over typically occurs during MEIOSIS but it may also occur in the absence of meiosis, for example, with bacterial chromosomes, organelle chromosomes, or somatic cell nuclear chromosomes.	Crossing Over,Crossing-Over, Genetic,Crossing Overs,Genetic Crossing Over,Genetic Crossing-Over
D004392	Dwarfism	A genetic or pathological condition that is characterized by short stature and undersize. Abnormal skeletal growth usually results in an adult who is significantly below the average height.	Nanism
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D012854	Sister Chromatid Exchange	An exchange of segments between the sister chromatids of a chromosome, either between the sister chromatids of a meiotic tetrad or between the sister chromatids of a duplicated somatic chromosome. Its frequency is increased by ultraviolet and ionizing radiation and other mutagenic agents and is particularly high in BLOOM SYNDROME.	Chromatid Exchange, Sister,Chromatid Exchanges, Sister,Exchange, Sister Chromatid,Exchanges, Sister Chromatid,Sister Chromatid Exchanges
D013577	Syndrome	A characteristic symptom complex.	Symptom Cluster,Cluster, Symptom,Clusters, Symptom,Symptom Clusters,Syndromes