Weathering and erosion. Weathering is the process where rock is dissolved, worn away or broken down into smaller and smaller pieces. There are mechanical, chemical and organic weathering processes.
What is trinucleotide repeat disorders? A class of genetic diseases that causes expansion of the number of trinucleotide (three base repeats of CG-rich units) within a gene sometimes associated with deleterious consequences.
Unstable trinucleotide repeats are associated with a variety of neurodegenerative diseases. Nine of these disorders are associated with expansion of cytosine-adenine-guanine (CAG) repeats that encode for polyglutamine tracts in the protein products. Included in this group are Huntington disease (HD), spinobulbar muscular atrophy, dentatorubral pallidoluysian atrophy, and some of the spinocerebellar ataxias.