Many examples of determination do too. In fact, organisms have evolved to exploit most or all of these control possibilities in various situations. In subsequent lectures we will discuss the mechanisms of developmental control at each of these levels. First, however, we will briefly discuss the genome as a whole, in terms of its size, information content, organization, and constancy during development. However, note that genome size is not necessarily a measure of biologically relevant information content.
Genome complexity is a better measure of at least the potential information content of the genome.
Some sample complexity values are shown in Table 1 at the end of these notes. Note that genome complexity is still not necessarily a measure of biologically relevant information content. Note that for metazoans, particularly vertebrates, the percentage of DNA complexity that represents coding sequences of genes is very small. Much better estimates for number of genes are now coming from sequencing entire genomes and using computer analysis to identify active genes from their sequence characteristics. The Drosophila sequence, which should be completed this spring, is now thought to include about 16,000 genes.