The given graph shows variations in the DNA content in the cells of a eukaryote. Haploid set of chromosomes 1C is present in gamete which on fertilisation with gamete of opposite sex acquires diploid set of chromosomes (2C) and transforms into embryo. Embryo develops and grows into diploid organism by multiple mitotic divisions. During sexual reproduction, gamete formation takes place by meiotic division under which initial amount of DNA(2C) increases to 4C during S phase, which in first meiotic division reduces to half i.e., 2C, divided among two daughter cells whereas chromosomal number reduces to half i.e., from 2n to n. During second meiotic division, the amount of DNA is further distributed equally from each daughter cells (from first meiotic division) to two daughter cells. The second meiotic division is equational, therefore the number of chromosome remains the same as produced at the end of meiosis I. Thus at the end of meiosis-II, each of the four haploid daughter cells contains one copy of every chromosome in the set (1C), rather than two.
