The initial polypeptide can be cut into different functional pieces, with different patterns of cleavage occurring in different tissues. In some cases, different pieces may be spliced together. Protein function can be modified by addition of methyl, phosphoryl, or glycosyl groups. Signal sequences direct packaging and secretion. The signal sequences usually end up cleaved off.
Gene expression is subject to many levels of control.
Outline the mechanisms at all the levels of control, from gene sequence to final product. Explain why control is useful at different levels. Genotype and phenotype of grl. Chemical mutagenesis of a large population of zebrafish yielded some deformed embryos. A point substitution resulted in partial loss of function of the gene product.