Giant chromosomes, light micrograph. These giant (polytene) chromosomes are from the salivary glands of the fruit fly Drosophila melanogaster. These c

---

Giant chromosomes, light micrograph. These giant (polytene) chromosomes are from the salivary glands of the fruit fly Drosophila melanogaster. These chromosomes are formed from repeated sequences of DNA (deoxyribonucleic acid) replication without nuclear division. A process known as endoreduplication. Polytene chromosomes increase cell volume and metabolic rate, as there are more genes to be expressed. The size of the chromosomes also allows for easy study by scientists. These chromosomes have been highlighted using an Orcein stain. Magnification: x400 when printed at 10 centimetres across.

---

Size: 3330px × 2639px
Photo credit: © ROBERT MARKUS/SCIENCE PHOTO LIBRARY / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: africa, britain, circle, circles, circular, earth, europe, france, image, images, mediterranean, north, photo, photos, rounded, science, sciences, shape, spain