We have identified a chromosome duplication in the pericentromeric region of human chromosome 11 located in 11p11 and 11q14. A detailed physical map of each duplicated region was generated to describe the nature of the duplication, the involvement at the centromere and to resolve the correct maps. All clones were evaluated to ensure they were representative of their genetic origin. The order of clones, based on their marker content, as well as the distance covered was determined by SEGMAP. Each duplication encompasses more than 1 Mb of DNA and appears to be chromosome 11 specific. Ten STS markers were mapped within each duplication. Comparative sequence analysis along the duplication identified 35 nucleotide changes in 2,036 bp between the two copies, suggesting the duplication occurred over 14 million years ago. A suggested organization of the pericentromeric region, including the duplications and alpha-related repetitive sequences, is presented.
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http://dx.doi.org/10.1159/000048805 | DOI Listing |
The 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.
View Article and Find Full Text PDFBMC Genomics
December 2024
Department of Biological Sciences, Seoul National University, Seoul, Korea.
Background: Plants possess a high potential for somatic cell reprogramming, enabling the transition from differentiated tissue to pluripotent callus, followed by the formation of de novo shoots during plant regeneration. Despite extensive studies on the molecular network and key genetic factors involved in this process, the underlying epigenetic landscape remains incompletely understood.
Results: Here, we explored the dynamics of the methylome and transcriptome during the two-step plant regeneration process.
EMBO J
December 2024
Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh, EH9 3BF, United Kingdom.
Genomes are organised into DNA loops by the Structural Maintenance of Chromosomes (SMC) proteins. SMCs establish functional chromosomal sub-domains for DNA repair, gene expression and chromosome segregation, but how SMC activity is specifically targeted is unclear. Here, we define the molecular mechanism targeting the condensin SMC complex to specific chromosomal regions in budding yeast.
View Article and Find Full Text PDFComp Cytogenet
December 2024
Zoological Institute, Russian Academy of Sciences, St. Petersburg, Russia Zoological Institute, Russian Academy of Sciences St. Petersburg Russia.
To identify nucleolus organizing regions (NORs), fluorescence hybridization (FISH) with 18S rDNA probe was performed on chromosomes of Linnaeus, 1758 (Tenthredinidae), (Linnaeus, 1767) (Argidae) (n = 10 in both) and (Bouché, 1834) (Cynipidae) (2n = 20). In all these species, a single pericentromeric rDNA cluster per haploid karyotype was detected. This number of NORs is confirmed as ancestral for the order Hymenoptera.
View Article and Find Full Text PDFThe current reference genome of , GRCm39, has major gaps in both euchromatic and heterochromatic regions associated with repetitive sequences. In this work, we have sequenced and assembled the telomere-to-telomere genome of mouse haploid embryonic stem cells. The results reveal more than 7.
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