The chromosomal theory of inheritance is a fundamental theory of genetics that recognizes chromosomes as the bearers of genetic material. According to this theory, genes are the units of heredity and are found in the chromosomes. The theory was proposed by Theodor Boveri and Walter Sutton in the early 1900s. During Mendels experimentation, society was not accepting of such drastic changes in their scientific ideas. They could not believe the existence of such discrete factors such as genes that would segregate without mixing, as this did not support their idea of the constant changes leading to evolution. The idea of chromosomal segregation combined with the Mendelian principles gave rise to the chromosomal theory of inheritance.
The chromosomal theory of inheritance supports Mendels laws. The observations of this theory include:
- During the process of cell division-meiosis, the pairs of homologous chromosomes move as discrete structures, which are independent of other pairs of chromosomes.
- There is a random distribution of chromosomes into the pre-gametes from each homologous pair.
- Each parent synthesizes gametes, which constitute only half of their chromosomal complement.
The theory and laws of genetics can be explained well with the help of three points or observations. The first point is that chromosomes come in pairs. The second point is that these pairs of chromosomes migrate as discrete structures independent of other chromosome pairs during the process of cell division-meiosis. The third point is that chromosomes of each homologous pair are randomly distributed into pre-gametes. Gametes are synthesized by each parent and contain just half of their chromosomal complement. The pattern of behavior of the chromosomes during meiosis explains the Mendelian laws, as to why and how genes are inherited.
