Types of chromosome classification. Chromosomes from Class-1 and Class-2 are individually separated. Both classes are differentiated by their straightness, i.e., Class-1 is straight individual chromosome while Class-2 is individually separable but with bended or skewed structure. Class-3 chromosomes are those that appear touching/overlapping with other chromosomes. Finally, Class-4 is characterized as non-chromosome residues and to be excluded in future analyses.