Sonneborn in 1938 discovered certain strains in Paramecium which showed a killer trait due to the presence of a cytoplasmic factor called kappa. The killer strain can destroy the sensitive strains growing in culture which do not have kappa by liberating a toxic substance paramecin. Killer strains are not killed by their own paramecin. Paramecium has two kinds of nuclei, [...]
In this article we will discuss about the chromosome theory of inheritance. In order to understand the role played by chromosomes as carriers of hereditary material, we must turn the clock backward to some landmarks in the history of genetics. The earliest records date back to the work of the 18th Century plant hybridisers. One of them Kolreuter had some [...]
In this article we will discuss about:- 1. Meaning of Meiosis 2. Occurrence of Meiosis 3. Genetics 4. The Spindle Apparatus 5. Forces Required for Chromosome Movement 6. Regulation of the Cell Cycle. Meaning of Meiosis: The division which takes place in cells of the germ line is called meiosis (Fig. 6.2). It results in four products of a parent [...]