RNAs are the direct products of genes, and these small RNAs can bind to other specific messenger RNA (mRNA) molecules and either increase or decrease their activity, for example by preventing an mRNA from producing a protein.
What causes stretch marks? Stretch marks are caused when the skin rapidly stretches as a result of sudden growth or weight gain. The stretching causes the middle layer of skin (dermis) to tear, allowing the deeper skin layers to show through, forming stretch marks. The dermis contains strong, inter-connected fibres that allow your skin to stretch as your body grows.
Stretch marks can appear when there is rapid stretching of the skin. They are often seen when a woman's abdomen gets larger during pregnancy. They can be found in children who have become rapidly obese. They may also occur during the rapid growth of puberty in males and females.