Comparative Genomics in Eukaryotes

was coined in 1920 (see Chapter 1), the general concept goes back at least as far as the 4th century BCE, when Aristotle implicated blood as the heredity substance. The blood of the mother, it was thought, supplied matter to the developing fetus whereas the semen (a purified form of blood) of the father conveyed form (Aristotle, 1953). Ironically, although the notions of “blood relations” and characteristics being “in one’s blood” persist, it is now known that the blood of mammals actually contains very little genetic material because their erythrocytes contain neither nuclei nor mitochondria (see Chapter 1). As scientific method and technique advanced, heredity eventually came to be associated with bodies called chromosomes in the nuclei of cells (late 19th and early 20th centuries) and finally with the long double-stranded nucleotide polymers called DNA molecules that are wound up within those chromosomes (mid-20th century). This chapter outlines the development and current status of comparative eukaryotic genomics, from the earliest studies of basic chromosome structure to the sequencing of entire genomes. In the process, a review is provided of the structure, organization, and composition of the primary eukaryotic genomes that have been sequenced thus far. This is a truly exciting time for the biological