Molecular Regulation and Signaling in Embryology Quiz

Sequencing the human genome, together with creating techniques to investigate gene regulation at many levels of complexity, has taken embryology to the next level. Thus, from the anatomical to the biochemical to the molecular level, the story of embryology has progressed, and each chapter has enhanced our knowledge. Histone complex Embryonic development is directed by genomes that contain all of the information required to make an individual. The information is encoded in DNA in sequences called genes that code for proteins. In turn, proteins regulate expression of other genes and act as signal molecules to orchestrate development. FIGURE 1.1 Drawing showing nucleosomes that form the basic unit of chromatin. Each nucleosome consists of an octamer of histone proteins and approximately 140 base pairs of DNA. Nucleosomes are joined into clusters by linker DNA and other histone proteins. There are approximately 23,000 genes in the human genome, which represents only one-fifth of the number (100,000) predicted prior to completion of the Human Genome Project. Because and its basic unit of structure is the nucleosome of various levels of regulation, however, the number of proteins derived from these genes is closer to the original predicted number of genes.