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While mutational biases strongly influence neutral molecular evolution, the role of mutational biases in shaping the course of adaptation is less clear. Here we consider the frequency of transitions relative to transversions among adaptive substitutions. Because mutation rates for transitions are higher than those for transversions, if mutational biases influence the dynamics of adaptation, then transitions should be overrepresented among documented adaptive substitutions. To test this hypothesis, we assembled two sets of data on putatively adaptive amino acid replacements that have occurred in parallel during evolution, either in nature or in the laboratory. We find that the frequency of transitions in these data sets is much higher than would be predicted under a null model where mutation has no effect. Our results are qualitatively similar even if we restrict ourself to changes that have occurred, not merely twice, but three or more times. These results suggest that the course of adaptation is biased by mutation.
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http://dx.doi.org/10.1093/molbev/msx180 | DOI Listing |
Eur J Clin Microbiol Infect Dis
September 2025
School of Bioengineering and Biosciences, Department of Biochemistry, Lovely Professional University, Punjab, 144411, India.
Purpose: This study investigates codon usage and amino acid usage bias in the genus Acinetobacter to uncover the evolutionary forces shaping these patterns and their implications for pathogenicity and biotechnology.
Methods: Codon usage patterns were examined in representative genomes of the genus Acinetobacter using standard codon bias indices, including GC content, relative synonymous codon usage (RSCU), effective number of codons (ENC), and codon adaptation index (CAI). Neutrality and parity plots were employed to evaluate the relative influence of mutational pressure and natural selection on codon preferences.
Cancer Genet
August 2025
Clinical Hematology and BMT Unit, Bahrain Oncology Center, Road 2835, Block 228, P.O. Box 24343, Busaiteen, Kingdom of Bahrain. Electronic address:
Complex chromosomal changes in Acute Myeloid Leukemia (AML) are highly heterogeneous, with disease progression shaped by both the number and nature of abnormalities. Rarely do, multiple unrelated clones with independent chromosomal changes coexist at diagnosis. Present study showcases a comprehensive characterization of two cytogenetically distinct complex clones in AML, driven by non-cyclic and chromoplexy mechanisms, highlighting their co-existence with key molecular alterations (TP53, NF1, DNMT3A, TET2) along with their potential contribution to clonal evolution.
View Article and Find Full Text PDFPestic Biochem Physiol
November 2025
Key Laboratory of Forest Disaster Warning and Control of Yunnan Province, Southwest Forestry University, Kunming 650224, China. Electronic address:
The cerambycid beetles are important components in the terrestrial ecosystem as they play a dual role in both degrading dying trees and killing healthy plants. The factors including human activity, habitat contraction, climate changes and pesticide use have been shaping the adaptation of beetles to host plants and the environment. As suggested in research on the functions of beetles' olfactory proteins, odorant binding proteins (OBPs) have been found to be involved in insecticide resistance other than chemoreception.
View Article and Find Full Text PDFClin Transl Oncol
September 2025
Spanish Society of Medical Oncology (SEOM) Thrombosis and Cancer Group, Madrid, Spain.
Purpose: To determine the real-world incidence and predictive factors for venous and arterial thromboembolic events (VTE/AT) in ovarian cancer patients treated with poly-(ADP-ribose) polymerase inhibitors (iPARP).
Methods/patients: A multicenter retrospective study involving 329 ovarian cancer patients who initiated iPARP treatment between January 2015 and December 2022. The primary outcome was the incidence of VTE/AT.
Clin Chim Acta
September 2025
Department of Hematology and Blood Banking, School of Allied Medical Sciences, Iran University of Medical, Tehran, Iran. Electronic address:
Acute myeloid leukemia (AML) represents a genetically heterogeneous malignancy, with mutations in the nucleophosmin-1 (NPM1) gene identified as the most prevalent and clinically significant molecular biomarkers. These mutations play a crucial pivotal role in the realms of diagnosis, prognosis, and therapeutic decision-making. Although an ideal measurable residual disease (MRD) test has yet to be developed, there is increasing acknowledgment of the significance of advanced molecular methodologies for monitoring MRD in NPM1-mutated (NPM1) AML.
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