 Genetics can be classified into four sub-disciplines, although some of the geneticists and researchers they classify genetics into many sub-disciplines. But most of the geneticists they classify genetics into four sub-disciplines. The four sub-disciplines of the genetics they are transmission or classical genetics, population genetics, quantitative genetics, as well as molecular genetics. So these are the four sub-disciplines of the genetics, but those geneticists that classify genetics into many sub-disciplines, these are the major sub-disciplines of the genetics, that deals with the genetics at molecular level, cytogenetics, where we study genetics, the chromosomes and the bending pattern of the chromosomes. If we study bending pattern of the chromosomes then this branch of genetics is called as cytogenetics. While in case of Mendelian genetics, one study the genetics about all those laws that were developed by the gregal mandel, the laws of heredity that comes under the heading of Mendelian genetics, plant and animal genetics. If we study the genetics of the plants or the genetics of the animals, then this sub-category of the genetics is called as plant and animal genetics. While population genetics, if we study the genetics of a specific population or the people which are present in a particular area, then this type of the genetics is called as population genetics. And if we study the genetics of the microbes like the genetics of the bacteria, genetics of the viruses, then this category of the genetics is called as microbial genetics. So these are all sub-divisions or sub-categories of the genetics. If we see the developments of the genetics and historically transmission genetics was developed first, which is also called as Mendelian genetics. Later on population genetics was developed and then quantitative genetics and the last molecular genetics was developed historically. If we see that what is transmission or classical genetics, transmission or classical genetics deals with the movement of genes, chromosomes or traits from parents into the offspring. This type of the genetics also deals with genetic recombinations. In case of population genetics, we study certain traits in a specific population. If certain traits are studied in a specific population, either that is determined by a single gene or that is determined by more than one gene, this type of the genetics is called as population genetics. Quantitative genetics, quantitative genetics deals with those characters which are determined by more than one gene, means more than one gene simultaneously determined for certain traits. This kind of genetics is called as quantitative genetics like the skin color, like the height of the humans as well as eye color of the humans. There are many genes which control eye color of the humans, height of the humans as well as skin color of the humans. So this type of the genetics is quantitative genetics. Fourth and the last type of the genetics that is molecular genetics. If we study genetics at the level of molecule at the level of DNA or RNA or we identify certain mutations or the sequence of the DNA, then this type of the genetics is called as molecular genetics. So these are four major sub-disciplines of the genetics. Some geneticists, they classify genetics into four, but there are many geneticists, they classify genetics into more than four sub-disciplines.