Collinearity (colinearity)

Collinearity occurs when amino acid sequences in the polypeptide correspond to the codon sequences in nucleic acids, the 5′ end of the mRNA matching with the NH2 end of the polypeptide chain. Some Drosophila genes, e.g., within the ANTC (Antennapeadia complex, chromosome 3-47.5) appear the same sequence in the map as the morphogenetic function they control (lab, Pb, Dfd, Scr, Antp). Similar collinearity has been shown in the BXC (Bithorax complex) Ultrabithorax segment. (Collinearity is spelled with two ls because derived from the Latin cu m + l inearis [collineo]). In the homeotic complexes generally there is another “position effect”; the products of the relatively posterior acting genes appear to be more abundant than that of the anterior ones. Recent information indicates that collinearity is not completely valid for some/most parts of the genome because the same genetic elements are used differently in different contexts of genes and form an interleaved or modular genomic...