The following points highlight the six main parts of a chromosome. The parts are: 1. Pellicle and Matrix 2. Chromatids, Chromonema and Chromomeres 3. Centromeres 4. Secondary Constriction 5. Satellite 6. Telomere. Part # 1. Pellicle and Matrix: A membrane which surrounds each chromosome is said as pellicle. A jelly substance present inside the membrane is called as matrix. Presumably [...]
In this article we will discuss about:- 1. Meaning of Chromosomes 2. Number of Chromosomes 3. Size 4. Chemical Composition 5. Functions 6. Special Types. Meaning of Chromosomes: Chromosomes are the most important constituents of the nucleus and were first observed by Holfmeister (1848) in pollen mother cell of Tradescantia and called it nuclear filaments. Chromosomes are filamentous bodies which [...]
In this article we will discuss about:- 1. Meaning of Crossing-Over 2. Example of Crossing Over in Drosophila 3. Theories 4. Mechanism 5. Kinds 6. Percentage 7. Cytological Evidence 8. Factors 9. Cytological Evidence 10. Significance 11. Interference and Coincidence. Meaning of Crossing-Over: The phenomenon of complete linkage occurs rarely since the linked genes tend to separate during meiotic divisions. [...]