The Colored Bodies of Cell Nuclei: Chromosomes and Heredity

Investigating cell division, Flemming noted that chromosomes were distributed to daughter nuclei in a process he dubbed mitosis (Greek for thread). Flemming fully deserves to be considered one of the founders of cytogenetics, a branch of cytology (cell science) dealing with the study of chromosomes. That the hereditary material is indeed located within or on the aforementioned colored intranucleic bodies constitutes the central tenet of the chromosome theory of inheritance advocated by several researchers in the first decade of the twentieth century. Work by, in particular, Walter Sutton and Theodor Boveri linked heredity, or the new science of genetics, with cytological observations in a manner that provided Mendel’s laws with a much needed anatomical backbone. The thread‐like chromosomes seen by Flemming and others were identified as the nucleic structures on which Mendel’s paired factors, now called genes, were sitting in a linear manner at specific sites called loci.