EVERYDAY SCIENCE

Detailed explanation-1: -In the late 1940s, Barbara McClintock challenged existing concepts of what genes were capable of when she discovered that some genes could be mobile. Her studies of chromosome breakage in maize led her to discover a chromosome-breaking locus that could change its position within a chromosome.

Detailed explanation-2: -In 1983, at the age of 81, she received the Nobel Prize in Physiology or Medicine for her work on “mobile genetic elements, ” that is, genetic transposition, or the ability of genes to change position on the chromosome. McClintock was the first woman to receive an unshared Nobel Prize in that category.

Detailed explanation-3: -Barbara McClintock discovers that genes can jump around on chromosomes, showing that the genome is more dynamic than previously thought. Since the studies on genetic linkage in Drosophila conducted in Morgan’s lab, genes had been considered to have fixed positions on chromosomes.

Detailed explanation-4: -A transposable element or jumping gene is a segment of DNA sequence that can change its position within the genome, sometimes creating or reversing mutations and altering the cell’s genome size. Barbara McClintock proposed the theory of jumping genes in maize.

Detailed explanation-5: -McClintock began her research into transposons by examining how genes combined in a process called crossing over. Prior to McClintock’s research, scientists had studied crossing-over. Crossing over is the process by which homologous chromosomes align side by side during meiosis and physically exchange genetic material.