Abstract
Few distinctions in biology are as clearly drawn as the one between mitosis and meiosis. The function of mitosis is to produce two identical daughter cells, while the purpose of the first division of meiosis is to ensure the segregation of homologous chromosomes, and the second division is to create haploid gametes. These meiotic segregations usually rely on meiosis-specific processes such as the induction of preprogramed double-strand breaks, homolog pairing, synaptonemal complex (SC) formation, synapsis, and recombination between homologs to form crossovers. While not all meiotic systems function identically, enough commonalities exist to allow us to draw clear distinctions between meiosis and mitosis. Mitotic cells simply do not build SC, and the process of full-length homolog pairing is almost always a prerogative of cells entering meiosis, not mitosis. Vexingly for those of us who like our distinctions made clearly, all this has changed, at least in Drosophila, as a result of two papers in this issue of PLOS Genetics [1], [2]. These authors show that although homologs are neither paired nor synapsed in germline stem cells (GSCs) of Drosophila females, both homolog pairing and the accumulation of SC components in pericentromeric regions initiate during the five mitotic divisions preceding meiosis. While the mechanisms and consequences of these interactions remain to be elucidated, it is clear that pairing and synapsis begin earlier than previously imagined—indeed, they initiate during the premeiotic mitotic divisions.
Highlights
For those of us who like our distinctions made clearly, all this has changed, at least in Drosophila, as a result of two papers in this issue of PLOS Genetics [1,2]
While the mechanisms and consequences of these interactions remain to be elucidated, it is clear that pairing and synapsis begin earlier than previously imagined—they initiate during the premeiotic mitotic divisions
To the best of our knowledge, this is the first demonstration of synaptonemal complex (SC) in mitotic cells of any organism and the first evidence that meiotic pairing in Drosophila is not the consequence of the pairing established in early embryogenesis
Summary
Few distinctions in biology are as clearly drawn as the one between mitosis and meiosis. The function of mitosis is to produce two identical daughter cells, while the purpose of the first division of meiosis is to ensure the segregation of homologous chromosomes, and the second division is to create haploid gametes. Mitotic cells do not build SC, and the process of full-length homolog pairing is almost always a prerogative of cells entering meiosis, not mitosis For those of us who like our distinctions made clearly, all this has changed, at least in Drosophila, as a result of two papers in this issue of PLOS Genetics [1,2]. While the mechanisms and consequences of these interactions remain to be elucidated, it is clear that pairing and synapsis begin earlier than previously imagined—they initiate during the premeiotic mitotic divisions
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
