The following points highlight the top four models proposed for chromosome structure. The models are: 1. Molecular Model 2. Multi-Stranded Model or Polyneme Chromosome Model 3. General Chromosome Model 4. Folded Fibre Model. Chromosome Structure: Model # 1. Molecular Model: This model of chromosome structure was proposed by Taylor and coworkers in 1957, 1963 and is based on the semiconservative [...]
In this article we will discuss about the changes in chromatin structure during transcription. Displacement of nucleosomes: During transcription, some changes in the chromatin structure occur in the region of transcription. RNA polymerase is comparatively larger in size than the nucleosomes. The molecular weight of RNA polymerase is about 5,00,000 Daltons, while that of nucleosome is about 2,60,000 Daltons. Lewin [...]
In this article we will discuss about:- 1. Coiled DNA Model 2. Nucleosome-Solenoid Model of Chromatin Fibres. Coiled DNA Model: This model of chromatin structure was proposed by DuPraw in 1965. As per this model, DNA molecule is associated with three classes of proteins: (i) Lysine rich histories: They are common to both A and B type fibres and are [...]