High levels of homologous recombination are induced during meiosis. This meiotic recombination is initiated by programmed formation of DNA double-strand breaks (DSBs) by a conserved meiosis-specific protein, Spo11. Meiotic DSBs are not formed at random along chromosomes but are formed in clusters known as recombination hot spots. To understand the regulation of this initiation step of meiotic recombination, determining the timing and location of meiotic DSBs is essential. In this chapter, we describe a method to detect genome-wide meiotic DSBs by using a combination of pulsed-field gel electrophoresis and Southern blotting.
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http://dx.doi.org/10.1007/978-1-61779-129-1_3 | DOI Listing |
Nucleic Acids Res
January 2025
MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Zhejiang University, No.866 Yuhangtang Road, 310058, Hangzhou, China.
Meiosis in mammalian oocytes is interrupted by a prolonged arrest at the germinal vesicle stage, during which oocytes have to repair DNA lesions to ensure genome integrity or otherwise undergo apoptosis. The FIRRM/FLIP-FIGNL1 complex dissociates RAD51 from the joint DNA molecules in both homologous recombination (HR) and DNA replication. However, as a type of non-meiotic, non-replicative cells, whether this RAD51-dismantling mechanism regulates genome integrity in oocytes remains elusive.
View Article and Find Full Text PDFGenetics
January 2025
Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
Bloom Syndrome helicase (Blm) is a RecQ family helicase involved in DNA repair, cell-cycle progression, and development. Pathogenic variants in human BLM cause the autosomal recessive disorder Bloom Syndrome, characterized by predisposition to numerous types of cancer. Prior studies of Drosophila Blm mutants lacking helicase activity or protein have shown sensitivity to DNA damaging agents, defects in repairing DNA double-strand breaks (DSBs), female sterility, and improper segregation of chromosomes in meiosis.
View Article and Find Full Text PDFMol Biol Evol
January 2025
Institut de Biologie, École Normale Supérieure, CNRS UMR 8197, Inserm U1024, PSL Research University, Paris, F-75005, France.
Modifiers of recombination rates have been described but the selective pressures acting on them and their effect on adaptation to novel environments remain unclear. We performed experimental evolution in the nematode Caenorhabditis elegans using alternative rec-1 alleles modifying the position of meiotic crossovers along chromosomes without detectable direct fitness effects. We show that adaptation to a novel environment is impaired by the allele that decreases recombination rates in the genomic regions containing fitness variation.
View Article and Find Full Text PDFPLoS Biol
January 2025
Research Group Meiotic Recombination and Genome Instability, Max Planck Institute for Evolutionary Biology, Plön, Germany.
A recent study in PLOS Biology on the epigenetic recombination regulator PRDM9 in salmonid fish reveals that its function has been preserved across vertebrates for hundreds of millions of years, with rapidly evolving DNA-binding domains being a defining attribute.
View Article and Find Full Text PDFThe centromere effect (CE) is a meiotic phenomenon that ensures meiotic crossover suppression in pericentromeric regions. Despite being a critical safeguard against nondisjunction, the mechanisms behind the CE remain unknown. Previous studies have shown that various regions of the pericentromere, encompassing proximal euchromatin, beta and alpha heterochromatin, undergo varying levels of crossover suppression, raising the question of whether distinct mechanisms establish the CE in these different regions.
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