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, [...]
Get the answer of: How Many Stages are in Mitosis ? 1. Prophase: The DNA in the diffuse chromatin of the resting nucleus in interphase has been duplicated in S phase preceding this cell division. The extended state of interphase chromatin allows transcription and replication of DNA, but is not suitable for division into two daughter cells. Therefore, prophase, the [...]
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 [...]