To determine the chromosomal location of mouse immunoglobulin heavy chain structural genes unambiguously, a panel of somatic cell hybrids was scored for the presence of DNA sequences homologous to gamma 2b-, mu-, and alpha-heavy chain-constant region DNA probe molecules. The hybrids, formed between mouse and hamster cells, contained various combinations of mouse chromosomes plus a full set of h...

Southern blot analysis of somatic cell hybrid lines indicates that the beta chain of the T cell receptor for antigen maps to chromosome 6 of the mouse. An experiment testing hybridization of the constant region of this gene to DNA from a hybrid cell line containing a translocation of chromosome 6 supports the localization of this gene to the proximal (centromeric) one-third of chromosome 6, in ...

Aberrations of the long arm of chromosome 1 have been linked to many diseases, both in acquired somatic neoplastic conditions and constitutional genetic disorders. These abnormalities include structural rearrangements and various deletions or amplifications affecting whole chromosome arms or specific regions. Gain of chromosome 1q has been reported in many solid tumours, including invasive carc...

A cDNA clone encoding the alpha chain of the human T cell receptor was used in connection with somatic cell human-rodent hybrids to determine that the genes coding for the alpha chain are located on chromosome 14 in humans. In situ hybridization confirms this result and further localizes these genes to 14q11-14q12 on this chromosome. Since this region of chromosome has been shown to be nonrando...

An inverse relationship between a volume estimated to be associated with interphase chromosomes and acute lethal exposure to x-or gamma radiation has been found in 16 plant species. The apparent differences in radiosensitivities found would seem spurious, since the estimated average energy absorbed in the nucleus per chromosome (3.6 x 10(6) ev) approaches a constant (variation less than fourfol...

Ninety-nine loci have been assigned to river buffalo chromosomes, 67 of which are coding genes and 32 of which are anonymous DNA segments (microsatellites). Sixty-seven assignments were based on cosegregation of cellular markers in somatic cell hybrids (synteny), whereas 39 were based on in situ hybridization of fixed metaphase chromosomes with labeled DNA probes. Seven loci were assigned by bo...

HE X-linked white locus of Drosophila melanogaster is a complex region of Tthe chromosome which has been subdivided into a number of sites (LEWIS 1952; MACKENDRICK and PONTECORVO 1952; GREEN 1959, 1964; JUDD 1959, 1964). Heterozygotes for two mutant alleles mapping at different sites in the white region (except for compounds with the right-most site, for white-spotted) do not show complementati...

Replicating the genome prior to each somatic cell division not only requires precise duplication of the genetic information, but also accurately reestablishing the epigenetic signatures that instruct how the genetic material is to be interpreted in the daughter cells. The mammalian inactive X chromosome (Xi), which is faithfully inherited in a silent state in each daughter cell, provides an exc...

For reprints contact: [email protected] X chromosome inactivation (XCI) is a strategy used by mammals to silence genes along one of the two female X chromosomes and equilibrate expression dosage between XY males and XX females. This epigenetically-inherited silencing is established during early embryonic development and maintained thereafter through cell divisions. Seeding of multiple repr...

Background: Cirrhinus mrigala, one of the important fish widely consumed in India, was used for karyological observations and to evaluate the toxic effect of butachlor, an extensively used herbicide in rice fields in terms of chromosomal aberration test. Methods: Fishes were collected from “National Fish Seed Farm” Jyotisar with mean body weight of 20-50g. The experimental fishes were kept i...