What is genetics ?
It is the study of inheritable characteristics that are given an identity by genes in an organism.
Genetics in simple terms is the study of genes, hereditary characteristics, and heritable variations in organisms.
Genetics tries to unravel how genes are responsible for encoding the traits we observe in an organism.
There are three different levels of genetics
Transmissible genetics which is basically studying how the hereditary traits are passed from parent. here we study the traits transmission at a singular organism level.
Molecular genetics which study the chemical nature of the gene itself and look at how the gene encode the genetic information which is replicated and then used by the organism in the form of protein. here we can even look at same gene across different species, individuals and types of organism. (example can include comparing human and yeast RNA Polymerase structure)
Population genetics studies the makeup of the population in one species with large number of individuals to study the variations in the species or gene pool. it also gives us the idea on how a species is evolved from its ancestors.
These there levels are not obsolete there can be different types of categories like fly genetics (based on organism) where scientist study about fruit fly genetics which can be divided in the above three categories.
Sometimes genetics is divided using structure in different specialized field of genes like chromosomal genetics, where you study about genetics about the chromosomes.