NLM IRP Seminar Schedule
UPCOMING SEMINARS
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March 28, 2024 Joseph Schafer
Evolutionary selection of proteins with two folds -
April 2, 2024 Yifan Yang
TBD -
April 4, 2024 Ermin Hodzic
TBD -
April 9, 2024 OPEN
TBD -
April 11, 2024 Sergey Shmakov
TBD
RECENT SEMINARS
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March 28, 2024 Joseph Schafer
Evolutionary selection of proteins with two folds -
March 26, 2024 Sanasar Babajanyan
Microbial diversity and ecological complexity emerging from environmental variation and horizontal gene transfer in a simple mathematical model -
March 19, 2024 MG Hirsch
Stochastic modeling of single-cell gene expression adaptation reveals non-genomic evolution of tumor subclones -
March 14, 2024 Mehari Bayou Zerihun
Identification of transcription factor binding sites with deep learning -
March 12, 2024 Sofya Garushyants
Synergistic anti-phage activity of bacterial defense systems
Scheduled Seminars on March 9, 2023
Contact NLM_IRP_Seminar_Scheduling@mail.nih.gov with questions about this seminar.
Abstract:
The availability of large numbers of bacterial genome sequences from the same species allows analysis of many polymorphisms of very recent origin. Data from the NCBI Pathogens project allows reconstruction of large numbers (over 100,000 for some species) of very recent single-nucleotide changes. I will present several studies of mutational hotspots and coding sequence evolution that are based on such data. The mutational phenomena include high transition rates at C5-methyl-cytosine, an extremely high C->A rate at certain N4-methylated cytosines, and tremendous acceleration of T->G mutation by preceding runs of G. Another study revealed positive selection for inactivation by nonsense mutations in dozens of Salmonella genes. Work on evolutionarily recent nonsynonymous changes, which have been only partially subjected to purifying selection, provides a window into purifying and positive selection on protein sequences that complements more distant comparisons. Analysis of recent changes affecting an E. coli clade that causes recurrent food-borne outbreaks revealed a likely genetic basis for this recurrence and a possible clue to the location of the reservoir of contamination.