Chromosomal theory of inheritence - Sutton and Boveri

Chromosomal Theory of Inheritance

• The eagerness regarding the behavior of chromosomes after the publication of Mendel work, was  increased among the  scientists. Most scientists  observed the function of  chromosomes during mitosis and meiosis.

• In 1902, Theodor Boveri observed that  the proper embryonic development in  sea urchins does not occur without the involvement of chromosomes .

• Walter Sutton observed the separation of chromosomes and migration of chromosomes  into daughter cells during meiosis.

• The observation of Sutton and Boveri  led to the proposal of chromosome theory of inheritance. The silent features of this theory are as -

• Genes are located at specific locations on the chromosomes. Chromosmes as well as genes both occur in pairs like factors as described by Mendel.

• Homologous chromosomes are moved randomly into gametes   or eggs and sperm. These gametes have half the number of chromosomes  from the parent cell.

• The gametes with half chromosomes are combined during fertilization to produce offspring with the same chromosome number as their parents.Therefore gametes are the link between the parents and the offspring.

• The movement of homologous chromosomes into gametes are independent from other pairs of chromosomes.

• Each parent produces gametes during gametogenesis that contain only half of their chromosomal .

• Though male gamete and female gamete are differ in size and morphology but both  have the same number of chromosomes. It reveals that  offspring get equal genetic contributions from each parent.

• The gametic chromosomes combine during fertilization to produce offspring with the same chromosome number as their parents.

• Chromosomes  are physical carriers of genetic material. All the hereditary characters are transmitted by gametes. Sperms and ova of the parents form the offspring .

• All the hereditary characters are transmitted through the chromosomes present in the nucleus of gametes. 

• Chromosomes are found in pairs like mendelian factors in somatic or diploid cells. During gamete formation homologous chromosomes pair and segregate independently at meiosis. The diploid condition is converted into haploid condition. 

• Homologous chromosomes are  segregated  as well as assort independently as described by Mendel, his monohybrid or dihybrid cross.