deoxyribonucleic acid, desoxyribonucleic acid, DNA(noun) (biochemistry) a long linear polymer found in the nucleus of a cell and formed from nucleotides and shaped like a double helix; associated with the transmission of genetic information.
But even adults don't often know what a notochord is. A notochord is a primitive beginning to the backbone. It appears in embryos as a small flexible rod made from cells from the mesoderm, which is one of the three layers of cells of embryos. Notochords are only found in the phylum chordata, a group of animals that includes humans.
The notochordâs position in the body differs among various animals. In protochordates, a rudimentary notochord is located on the dorsal side of the intestine in the proboscis. In the larvae of tunicates, it is located in the caudal section of the body. In acraniates and vertebrates, the notochord is located on the dorsal side of the body, under the neural tube and between the bands of the segmented musculature of the trunk.