Isochores are large DNA segments (>>300 kb on average) that are characterized by an internal variation in GC well below the full variation seen in the mammalian genome. Precisely defining in terms of size and composition as well as mapping the isochores on human chromosomes have, however, remained largely unsolved problems. Here we used a very simple approach to segment the human chromosomes de...

The human genetic material is packaged into 46 chromosomes. The structure of chromosomes is known at the lowest level, where the DNA chain is wrapped around a core of eight histone proteins to form nucleosomes. Around a million of these nucleosomes, each about 11 nm in diameter and 6 nm in thickness, are wrapped up into the complex organelle of the chromosome, whose structure is mostly known at...

In situ hybridization of human chromosomes appears as one of the most attractive methods of gene mapping since it enables the locus being looked for to be directly visualized. This technique however includes a critical step which is the denaturation of chromosomal DNA by different procedures such as heat, alkali or acid treatment (1). These affect the chromosome structure and decrease the good ...

Human pluripotent stem cells (PSCs) hold promise for treating a multitude of diseases. These fascinating cells are unique in their ability to both self-renew and differentiate into cells from all three germ layers. However, PSCs, as well as other cultured cells, are prone to genetic instability. Given the possibility that these cells may one day be used clinically, identifying, and perhaps prev...

Highly purified fractions of human chromosomes 21 and 22 were isolated from a suspension of metaphase chromosomes stained with ethidium bromide by using a fluorescence-activated cell sorter (FACS II). Two recombinant DNA libraries, representing chromosomes 21 and 22, were constructed by complete digestion of DNA from these fractions with EcoRI and insertion into the vector lambda gtWES lambda B...

A radiation hybrid (RH)-derived physical map of 25 markers on the feline X chromosome (including 19 Type I coding loci and 6 Type II microsatellite markers) was compared to homologous marker order on the human and mouse X chromosome maps. Complete conservation of synteny and marker order was observed between feline and human X chromosomes, whereas the same markers identified a minimum of seven ...

background: in human, sry (sex-determining region of the y chromosome) is the major gene for the testis-determining factor which is found in normal xy males and in the rare xx males, and it is absent in normal xx females and many xy females. there are several methods which can indicate a male genotype by the presence of the amplified product of sry gene. the aim of this study was to identify th...

We used fluorescence in situ hybridization (FISH) to study the positions of human chromosomes on the mitotic rings of cultured human lymphocytes, MRC-5 fibroblasts, and CCD-34Lu fibroblasts. The homologous chromosomes of all three cell types had relatively random positions with respect to each other on the mitotic rings of prometaphase rosettes and anaphase cells. Also, the positions of the X a...

The establishment of a model system of neoplastic transformation of normal human cells has been attempted with a chemical carcinogen, 4-nitroquinoline 1-oxide (4NQO). In the course of these experiments, it was noticed that immortalization of human cells is a multi-step process involving several mutational genetic events. Thus, chromosomal changes which occurred during the process of immortaliza...