The core promoter region is located most proximally and contains the RNA polymerase binding site, TATA box, and transcription start site (TSS). RNA polymerase will bind to this core promoter region stably and transcription of the template strand can initiate. The TATA box is a DNA sequence (5'-TATAAA-3) within the core promoter region where general transcription factor proteins and histones can bind.
The color palette of diamond is very richly varied; it ranges from pink through red, blue, green, yellow and brown even to black diamonds. The rarest color occurring in natural diamonds is red, followed by green, blue, purple and brown.
Alexandrite Color Alexandrite's green hue is a result of chromium impurities. Chromium is the same coloring element found in emerald, the green variety of precious beryl. Sri Lanka (Ceylon) alexandrite is known to exhibit a khaki to brown color change.hrysoberyl Cat's Eye. Alexandrite is a rare color change and chromium-bearing variety of chrysoberyl. There are a few other chrysoberyl varieties available; most are categorized because of an optical property, such as color, color change effect and chatoyancy.