Replication and segregation of eukaryotic chromosomal DNA.

Transmission of the genetic information from the parental to the two daughter cells resulting from each cell division requires this genetic information to be duplicated prior to cell division. This ensures that each daughter cell will inherit an exact and complete copy of the information contained in the parental cell. The duplication of the genetic information, which is codified in deoxyribonucleic acid (DNA), is called "DNA replication". During the last 33 years, since the structure of DNA was discovered by Watson and Crick (1953), DNA replication has been investigated using genetical, cytological, and molecular techniques. The present review is an attempt to summarize most of the knowledge that has been accumulated throughout these years on eukaryotic DNA replication, with special emphasis on the methodologies that have been employed. Besides, some of the current "hot spots" in this subject, such as the controversy concerning whether or not there are specific DNA sequences which are recognized as replication origins, the existence of a close association between replication timing and gene expression, and the mechanisms operating at the time of nascent replicon maturation and segregation of sibling DNA molecules, are discussed with special deference.