![]() Ī central role in the process of replication is played by activation of helicases, which break the hydrogen bonds holding the two DNA strands together and generate two single strands of DNA. They contain DNA sequences that are recognized by replication initiator proteins, such as the dnaA in Escherichia coli or the origin recognition complex (ORC) in yeast, which in turn recruit other proteins to separate the two strands and initiate replication –. ![]() In a cell, DNA replication begins at specific locations scattered across the genome called origins of replication –. ![]() As such, DNA replication is subject to a complex regulation in all eukaryotic organisms, which makes the identification of the underlying mechanism a non-trivial task. Severe malfunctions within DNA replication are usually lethal. The requisite for that is exact and efficient replication of the genome, a highly controlled cellular process, which makes up a large part of the cell cycle. One of the basic traits of all living systems is the ability to reproduce and transmit genomic information to their offspring. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Ĭompeting interests: The authors have declared that no competing interests exist. CD was supported by the Max Planck Society through IMPRS-CBSC (International Max Planck Research School for Computational Biology and Scientific Computing). TWS was supported by the German Research Foundation (DFG) through IRTG 1360 (International Research Training Group). This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.įunding: MB was supported by the Network of Excellence of the European Commission, Project ENFIN, contract number LSHG-CT-2005-518254. Received: JAccepted: MaPublished: April 27, 2010Ĭopyright: © 2010 Spiesser et al. The second division of meiosis is more similar to a mitotic division, except that the daughter cells do not contain identical genomes because of crossover.Citation: Spiesser TW, Diener C, Barberis M, Klipp E (2010) What Influences DNA Replication Rate in Budding Yeast? PLoS ONE 5(4):Įditor: Stefan Wölfl, Universität Heidelberg, Germany The homologous chromosomes separate into different nuclei during meiosis I, causing a reduction of ploidy level in the first division. The main differences between the processes occur in the first division of meiosis, in which homologous chromosomes are paired and exchange non-sister chromatid segments. Meiotic divisions include two nuclear divisions that produce four daughter nuclei that are genetically different and have one chromosome set instead of the two sets of chromosomes in the parent cell. Mitotic divisions are single nuclear divisions that produce daughter nuclei that are genetically identical and have the same number of chromosome sets as the original cell. Meiosis and mitosis share similarities, but have distinct outcomes. The cells that are produced by meiosis are genetically unique. The first separates homologs, and the second-like mitosis-separates chromatids into individual chromosomes.ĭuring meiosis, variation in the daughter nuclei is introduced because of crossover in prophase I and random alignment of tetrads at metaphase I. In meiosis, there are two rounds of nuclear division resulting in four nuclei and usually four daughter cells, each with half the number of chromosomes as the parent cell. Meiosis is a series of events that arrange and separate chromosomes and chromatids into daughter cells.ĭuring the interphases of meiosis, each chromosome is duplicated. ![]() As with mitosis, DNA replication occurs prior to meiosis during the S-phase of the cell cycle. Sexual reproduction requires that diploid organisms produce haploid cells that can fuse during fertilization to form diploid offspring.
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