User:Macdonald-ross/S2

Seymouria, from the early Permian.
National Museum of Natural History, Washington DC

Seymouria, for example, looked more like a reptile because it was so adapted to life in a drier climate. Nevertheless, it was an amphibian, and it did have a larval stage.

Diagram showing at which stages in the DNA-mRNA-protein pathway expression can be controlled

Senegal dancer

Gene regulation (or the regulation of gene expression) is used by cells to increase or decrease the production of gene products (protein or RNA).

Sophisticated programs of gene expression occur widely in biology, in fact they seem to be universal. Gene regulation is essential for all organisms because it increases the versatility and adaptability of an organism. It allows cells to adjust their biochemistry.

Furthermore, in multicellular organisms, gene regulation drives cellular differentiation and morphogenesis. Different cell types (tissues) are formed with different gene expression profiles. These different cell types produce different proteins and have different structures, which suit their functions. This happens even though they all have the genotype, which follows the same genome sequence.

Perhaps the first discovery of a gene regulation system was the identification in 1961 of the lac gene, discovered by Jacques Monod, in which some enzymes involved in lactose metabolism are expressed by the genome of E. coli only in the presence of lactose and absence of glucose.

Please do not cut out article sections on Simple English wikipedia as you did to "Endocrine system". Talk pages are there for a reason: please use them. Blanking pages without discussion may be treated as vandalism. Thank you.