Time to match; when do homologous chromosomes become closer?

Autor: M. Solé, J. Blanco, D. Gil, O. Valero, B. Cárdenas, G. Fonseka, E. Anton, Á. Pascual, R. Frodsham, F. Vidal, Z. Sarrate
Rok vydání: 2022
Předmět:
Zdroj: Dipòsit Digital de Documents de la UAB
Universitat Autònoma de Barcelona
ISSN: 1432-0886
0009-5915
Popis: Altres ajuts: acords transformatius de la UAB Altres ajuts: Universitat Autònoma de Barcelona CF-180034, CERCA Programme/Generalitat de Catalunya, PIF UAB In most eukaryotes, pairing of homologous chromosomes is an essential feature of meiosis that ensures homologous recombination and segregation. However, when the pairing process begins, it is still under investigation. Contrasting data exists in Mus musculus, since both leptotene DSB-dependent and preleptotene DSB-independent mechanisms have been described. To unravel this contention, we examined homologous pairing in pre-meiotic and meiotic Mus musculus cells using a three-dimensional fluorescence in situ hybridization-based protocol, which enables the analysis of the entire karyotype using DNA painting probes. Our data establishes in an unambiguously manner that 73.83% of homologous chromosomes are already paired at premeiotic stages (spermatogonia-early preleptotene spermatocytes). The percentage of paired homologous chromosomes increases to 84.60% at mid-preleptotene-zygotene stage, reaching 100% at pachytene stage. Importantly, our results demonstrate a high percentage of homologous pairing observed before the onset of meiosis; this pairing does not occur randomly, as the percentage was higher than that observed in somatic cells (19.47%) and between nonhomologous chromosomes (41.1%). Finally, we have also observed that premeiotic homologous pairing is asynchronous and independent of the chromosome size, GC content, or presence of NOR regions.
Databáze: OpenAIRE
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