Maize genetic diversity has been used to understand the molecular basis of phenotypic variation and to improve agricultural efficiency and sustainability. We crossed 25 diverse inbred maize lines to the B73 reference line, capturing a total of 136,000 recombination events. Variation for recombination frequencies was observed among families, influenced by local (cis) genetic variation. We identified evidence for numerous minor single-locus effects but little two-locus linkage disequilibrium or segregation distortion, which indicated a limited role for genes with large effects and epistatic interactions on fitness. We observed excess residual heterozygosity in pericentromeric regions, which suggested that selection in inbred lines has been less efficient in these regions because of reduced recombination frequency. This implies that pericentromeric regions may contribute disproportionally to heterosis.
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http://dx.doi.org/10.1126/science.1174320 | DOI Listing |
Chromosome Res
January 2025
Saint-Petersburg State University, Saint-Petersburg, Russia.
Danio rerio, commonly known as zebrafish, is an established model organism for the developmental and cell biology studies. Although significant progress has been made in the analysis of the D. rerio genome, cytogenetic studies face challenges due to the unclear identification of chromosomes.
View Article and Find Full Text PDFbioRxiv
December 2024
Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599.
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.
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