scholarly journals Evolution of $k$ -Mer Frequencies and Entropy in Duplication and Substitution Mutation Systems

2020 ◽  
Vol 66 (5) ◽  
pp. 3171-3186 ◽  
Author(s):  
Hao Lou ◽  
Moshe Schwartz ◽  
Jehoshua Bruck ◽  
Farzad Farnoud
Keyword(s):  
Substitution Mutation

scholarly journals Collagen XVII Is Destabilized by a Glycine Substitution Mutation in the Cell Adhesion Domain Col15

2000 ◽  
Vol 275 (5) ◽  
pp. 3093-3099 ◽  
Author(s):  
Kaisa Tasanen ◽  
Johannes A. Eble ◽  
Monique Aumailley ◽  
Hauke Schumann ◽  
Jens Baetge ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Collagen Xvii ◽  
Glycine Substitution ◽  
Substitution Mutation

scholarly journals Periodic variation of mutation rates in bacterial genomes associated with replication timing

2017 ◽  
Author(s):  
Marcus M. Dillon ◽  
Way Sung ◽  
Michael Lynch ◽  
Vaughn S. Cooper
Keyword(s):  
Vibrio Fischeri ◽  
Bacterial Species ◽  
Replication Timing ◽  
Small Chromosome ◽  
Burkholderia Cenocepacia ◽  
Mutation Rates ◽  
Base Substitution ◽  
Large Chromosome ◽  
Bacterial Genomes ◽  
Substitution Mutation

ABSTRACTThe causes and consequences of spatiotemporal variation in mutation rates remains to be explored in nearly all organisms. Here we examine relationships between local mutation rates and replication timing in three bacterial species whose genomes have multiple chromosomes:Vibrio fischeri, Vibrio cholerae, andBurkholderia cenocepacia. Following five evolution experiments with these bacteria conducted in the near-absence of natural selection, the genomes of clones from each lineage were sequenced and analyzed to identify variation in mutation rates and spectra. In lineages lacking mismatch repair, base-substitution mutation rates vary in a mirrored wave-like pattern on opposing replichores of the large chromosome ofV. fischeriandV. cholerae, where concurrently replicated regions experience similar base-substitution mutation rates. The base-substitution mutation rates on the small chromosome are less variable in both species but occur at similar rates as the concurrently replicated regions of the large chromosome. Neither nucleotide composition nor frequency of nucleotide motifs differed among regions experiencing high and low base-substitution rates, which along with the inferred ~800 Kb wave period suggests that the source of the periodicity is not sequence-specific but rather a systematic process related to the cell cycle. These results support the notion that base-substitution mutation rates are likely to vary systematically across many bacterial genomes, which exposes certain genes to elevated deleterious mutational load.

scholarly journals Induction of Micronuclei, Base-pair Substitution Mutation and Excision-repair Deficient by Polluted Water from Asa River in Nigeria

2019 ◽  
Vol 4 (2) ◽  
pp. 68-77
Author(s):  
Anifowoshe T Abass ◽  
Oladipo S Olayinka ◽  
Adebayo O Mutolib ◽  
Eboh O Solomon ◽  
Abdussalam A Rasheedat ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Base Pair ◽  
Water Samples ◽  
Ames Test ◽  
Excision Repair ◽  
Clarias Gariepinus ◽  
Polluted Water ◽  
Base Pair Substitution ◽  
Peripheral Erythrocyte ◽  
Substitution Mutation

AbstractAsa river is a major river designated to supply millions of people of Ilorin, Kwara State, Nigeria potable water for drinking but its managements is of grave concern due to anthropogenic activities. Thus, evaluation of genotoxicity of this river was carried out by subjecting the water samples and fish therein to three bioassays (Micronucleus (MN) assay, Ames test and SOS-chromo test). Physicochemical parameters and heavy metals were analysed at three different stations (Aliara (SI), Unity (SII) and Tuyil (SIII)) of the river. In SII, most of the heavy metals analysed were above the acceptable limits compare to SI and SIII. The peripheral erythrocyte of the fishes (Oreochromis niloticus, Synodontis batensoda, Synodontis eupterus, Clarias gariepinus and Clarias angullaris) at SI and SII stations showed a significant (p<0.05) induction of MN and different nuclear abnormalities (NA). Water samples from the three stations subjected to Ames test (Salmonella typhimurium TA100) and SOS chromotests (Escherichia coli PQ37) at 25%, 50% and 100% concentrations showed statistically significant (p<0.05) induction of DNA damage at all concentrations in the two tester strains, thus indicating base-pair substitution mutation and excision-repairdeficient, respectively, by the water samples. Therefore, drinking of this water and/or consumption of fish from this river should be taken with caution to avoid a carcinogenic risk.

scholarly journals Effects of DNA heterologies on bacteriophage lambda recombination.

Genetics ◽  
1988 ◽  
Vol 118 (1) ◽  
pp. 13-19
Author(s):  
R K Pearson ◽  
M S Fox
Keyword(s):  
Bacteriophage Lambda ◽  
Indirect Evidence ◽  
Direct Products ◽  
Base Pairs ◽  
Heteroduplex Dna ◽  
Deletion Mutations ◽  
Genetic Crosses ◽  
Insertion And Deletion ◽  
Progeny Phage ◽  
Substitution Mutation

Abstract Previous studies of bacteriophage lambda recombination have provided indirect evidence that substantial sequence nonhomologies, such as insertions and deletions, may be included in regions of heteroduplex DNA. However, the direct products of heterology-containing heteroduplex DNA--heterozygous progeny phage--have not been observed. We have constructed a series of small insertion and deletion mutations in the cI gene to examine the possibility that small heterologies might be accommodated in heterozygous progeny phage. Genetic crosses were carried out between lambda cI- Oam29 and lambda cI+ Pam80 under replication-restricted conditions. Recombinant O+P+ progeny were selected on mutL hosts and tested for cI heterozygosity. Heterozygous recombinants were readily observed with crosses involving insertions of 4 to 19 base pairs (bp) in the cI gene. Thus, nonhomologies of at least 19 bp can be accommodated in regions of heteroduplex DNA during lambda recombination. In contrast, when a cI insertion or deletion mutation of 26 bp was present, few of the selected recombinants were heterozygous for cI. Results using a substitution mutation, involving a 26-bp deletion with a 22-bp insertion, suggest that the low recovery of cI heterozygotes containing heterologies of 26 bp or more is due to a failure to encapsulate DNA containing heterologies of 26 bp or more into viable phage particles.

Identification of a novel substitution mutation (R103C) in the rod domain of the keratin 17 gene associated with pachyonychia congenita type 2

2018 ◽  
Vol 58 (2) ◽  
pp. 233-236 ◽  
Author(s):  
Feras M. Ghazawi ◽  
Kimya Hassani-Ardakani ◽  
Lisa Henriques ◽  
Fatemeh Jafarian
Keyword(s):  
Keratin 17 ◽  
Substitution Mutation ◽  
Pachyonychia Congenita
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