Specific staining of human chromosomes in Chinese hamster x man hybrid cell lines demonstrates interphase chromosome territories

In spite of Carl Rabl's (1885) and Theodor Boveri's (1909) early hypothesis that chromosomes occupy discrete territories or domains within the interphase nucleus, evidence in favor pf this hypothesis has been limited and indirect so far in higher plants and animals. The alternative possibility that the chromatin fiber of single chromosomes might be extended throughout the major part of even the whole interphase nucleus has been considered for many years. In the latter case, chromosomes would only exist as discrete chromatin bodies during mitosis but not during interphase. Both possibilities are compatible with Boveri's well established paradigm of chromosome individuality. Here we show that an active human X chromosome contained as the only human chromosome in a Chinese hamster x man hybrid cell line can be visualized both in metaphse plates and in interphase nuclei after in situ hybridization with either 3H- or biotin-labeled human genomic DNA. We demonstrate that this chromosome is organized as a distinct chromatin body throughout interphase. In addition, evidence for the territorial organization of human chromosomes is also presented for another hybrid cell line containing several autosomes and the human X chromosome. These findings are discussed in the context of our present knowledge of the organization and topography of interphase chromosomes. General applications of a strategy aimed at specific staining of individual chromosomes in experimental and clinical cytogenetics are briefly considered

A need for logical and consistent anatomical nomenclature for cutaneous nerves of the limbs

The system of anatomical nomenclature needs to be logical and consistent. However, variations in translation to English of the Latin and Greek terminology used in Nomina Anatomica and Terminologia Anatomica have led to some inconsistency in the nomenclature of cutaneous nerves in the limbs. An historical review of cutaneous nerve nomenclature reveals that there are two general naming conventions: one primarily American and one primarily British. The American convention presents cutaneous nerves of the limbs in the format “medial brachial cutaneous nerve,” while the British convention presents the same nerve as “medial cutaneous nerve of the arm,” thereby translating “brachii” to “of the arm.” If logically and consistently applied throughout the body, the British convention would rename the sural nerve to the “nerve of the calf,” the brachial artery would become the “artery of the arm,” the femoral nerve would be “nerve of the thigh,” and femur would be “bone of the thigh” or “thigh bone.” The British convention leads to many other nomenclatural inconsistencies, which would seem to make learning anatomy more difficult for the beginning student. In this era of contracting anatomy curricula, every effort should be made to keep anatomical nomenclature simple, logical, and consistent. Anat Sci Ed 2:126–134, 2009. © 2009 American Association of Anatomists.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63079/1/90_ftp.pd

Spatial Genome Organization:From Development to Disease

Every living organism, from bacteria to humans, contains DNA encoding anything from a few hundred genes in intracellular parasites such as Mycoplasma, up to several tens of thousands in many higher organisms. The first observations indicating that the nucleus had some kind of organization were made over a hundred years ago. Understanding of its significance is both limited and aided by the development of techniques, in particular electron microscopy, fluorescence in situ hybridization, DamID and most recently HiC. As our knowledge about genome organization grows, it becomes apparent that the mechanisms are conserved in evolution, even if the individual players may vary. These mechanisms involve DNA binding proteins such as histones, and a number of architectural proteins, some of which are very much conserved, with some others having diversified and multiplied, acquiring specific regulatory functions. In this review we will look at the principles of genome organization in a hierarchical manner, from DNA packaging to higher order genome associations such as TADs, and the significance of radial positioning of genomic loci. We will then elaborate on the dynamics of genome organization during development, and how genome architecture plays an important role in cell fate determination. Finally, we will discuss how misregulation can be a factor in human disease

Une Bible enluminée par Joseph ibn Hayyim

Wischnitzer Rachel. Une Bible enluminée par Joseph ibn Hayyim. In: Revue des études juives, tome 73, n°146, octobre-décembre 1921. pp. 161-172