In this article we will discuss about:- 1. Background of Chromosomes 2. Location of Chromosomes 3. Number 4. Shape 5. Size 6. Chemistry 7. Chemical Components 8. Physiology. Historical Background of Chromosomes: i) The term chromosome (Gr. chromo, color; soma, body), when used by Waldeyer in 1888, represented the darkly stained individualized bodies located in the nucleus. ii) Walter S. [...]
The morphologic characteristics of chromosomes are best studied during metaphase and anaphase of cell division. The chromosome was supposed to be covered by a membranous Pellicle. Electron microscope studies later showed that there is no definite membranous pellicle surrounding the chromosomes. A matrix of some sort, possibly protein, lipid, may be present. Other structures present in the chromosome include the [...]
The following points highlight the eight main criticisms for Lyon’s hypothesis. Criticism # 1. That XO, XXX, XY, XX etc. individual differ among themselves suggesting that the entire X chromosome is not genetically inactive. If it were so, an XX and XXX female would have had no difference at all. From various chemical stigmata it seems that a part of [...]