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 [...]
Plastids are cytoplasmic organelles which contain DNA and duplicate themselves independently of nuclear genes, and are distributed more or less equally to daughter cells during mitosis. While studying leaf pigmentation in Mirabilis jalapa (four O'clock plant), Correns (1909) found for the first time that plastids could be transmitted to the offspring through the egg cytoplasm. In a variegated strain of [...]
The following points highlight the three main types of inheritance with its characteristics. The types are: 1. Autosomal Dominant Inheritance 2. Autosomal Recessive Inheritance 3. Polygenic Disorders and Multifactorial Inheritance. Type # 1. Autosomal Dominant Inheritance: Farabee in 1905 gave the first description of a pedigree showing brachydactyly (short fingers and toes), an autosomal dominant trait. Some more examples are [...]