In the 1940's, while studying genetic inheritance in corn plants, barbara mcclintock discovered that segments of dna could move from one place to another on a chromosome and even move from one chromosome to another. the moving segments cause genetic variation and some changes are suspected to cause such genetic disorders as breast cancer and leukemia. mcclintock received a nobel prize for her work in genetics. these movable segments are now called a) dna sequencing. b) recombinant dna. c) transposons or jumping genes. d) transgenic or mcclintock plasmids.