scholarly journals De novo mutations across 1,465 diverse genomes reveal novel mutational insights and reductions in the Amish founder population

2019 ◽  
Author(s):  
Michael D. Kessler ◽  
Douglas P. Loesch ◽  
James A. Perry ◽  
Nancy L. Heard-Costa ◽  
Brian E. Cade ◽  
...  

Abstractde novo Mutations (DNMs), or mutations that appear in an individual despite not being seen in their parents, are an important source of genetic variation whose impact is relevant to studies of human evolution, genetics, and disease. Utilizing high-coverage whole genome sequencing data as part of the Trans-Omics for Precision Medicine (TOPMed) program, we directly estimate and analyze DNM counts, rates, and spectra from 1,465 trios across an array of diverse human populations. Using the resulting call set of 86,865 single nucleotide DNMs, we find a significant positive correlation between local recombination rate and local DNM rate, which together can explain up to 35.5% of the genome-wide variation in population level rare genetic variation from 41K unrelated TOPMed samples. While genome-wide heterozygosity does correlate weakly with DNM count, we do not find significant differences in DNM rate between individuals of European, African, and Latino ancestry, nor across ancestrally distinct segments within admixed individuals. However, interestingly, we do find significantly fewer DNMs in Amish individuals compared with other Europeans, even after accounting for parental age and sequencing center. Specifically, we find significant reductions in the number of T→C mutations in the Amish, which seems to underpin their overall reduction in DNMs. Finally, we calculate near-zero estimates of narrow sense heritability (h2), which suggest that variation in DNM rate is significantly shaped by non-additive genetic effects and/or the environment, and that a less mutagenic environment may be responsible for the reduced DNM rate in the Amish.SignificanceHere we provide one of the largest and most diverse human de novo mutation (DNM) call sets to date, and use it to quantify the genome-wide relationship between local mutation rate and population-level rare genetic variation. While we demonstrate that the human single nucleotide mutation rate is similar across numerous human ancestries and populations, we also discover a reduced mutation rate in the Amish founder population, which shows that mutation rates can shift rapidly. Finally, we find that variation in mutation rates is not heritable, which suggests that the environment may influence mutation rates more significantly than previously realized.

2020 ◽  
Vol 10 (9) ◽  
pp. 3309-3319 ◽  
Author(s):  
Ajith V Pankajam ◽  
Suman Dash ◽  
Asma Saifudeen ◽  
Abhishek Dutta ◽  
Koodali T Nishant

Abstract A growing body of evidence suggests that mutation rates exhibit intra-species specific variation. We estimated genome-wide loss of heterozygosity (LOH), gross chromosomal changes, and single nucleotide mutation rates to determine intra-species specific differences in hybrid and homozygous strains of Saccharomyces cerevisiae. The mutation accumulation lines of the S. cerevisiae hybrid backgrounds - S288c/YJM789 (S/Y) and S288c/RM11-1a (S/R) were analyzed along with the homozygous diploids RM11, S288c, and YJM145. LOH was extensive in both S/Y and S/R hybrid backgrounds. The S/Y background also showed longer LOH tracts, gross chromosomal changes, and aneuploidy. Short copy number aberrations were observed in the S/R background. LOH data from the S/Y and S/R hybrids were used to construct a LOH map for S288c to identify hotspots. Further, we observe up to a sixfold difference in single nucleotide mutation rates among the S. cerevisiae S/Y and S/R genetic backgrounds. Our results demonstrate LOH is common during mitotic divisions in S. cerevisiae hybrids and also highlight genome-wide differences in LOH patterns and rates of single nucleotide mutations between commonly used S. cerevisiae hybrid genetic backgrounds.


2022 ◽  
pp. gr.276103.121
Author(s):  
Daniel Melamed ◽  
Yuval Nov ◽  
Assaf Malik ◽  
Michael B Yakass ◽  
Evgeni Bolotin ◽  
...  

While it is known that the mutation rate varies across the genome, previous estimates were based on averaging across various numbers of positions. Here we describe a method to measure the origination rates of target mutations at target base positions and apply it to a 6-bp region in the human hemoglobin subunit beta (HBB) gene and to the identical, paralogous hemoglobin subunit delta (HBD) region in sperm cells from both African and European donors. The HBB region of interest (ROI) includes the site of the hemoglobin S (HbS) mutation, which protects against malaria, is common in Africa and has served as a classic example of adaptation by random mutation and natural selection. We found a significant correspondence between de novo mutation rates and past observations of alleles in carriers, showing that mutation rates vary substantially in a mutation-specific manner that contributes to the site frequency spectrum. We also found that the overall point mutation rate is significantly higher in Africans than in Europeans in the HBB region studied. Finally, the rate of the 20A→T mutation, called the 'HbS mutation' when it appears in HBB, is significantly higher than expected from the genome-wide average for this mutation type. Nine instances were observed in the African HBB ROI, where it is of adaptive significance, representing at least three independent originations; no instances were observed elsewhere. Further studies will be needed to examine mutation rates at the single-mutation resolution across these and other loci and organisms and to uncover the molecular mechanisms responsible.


2017 ◽  
Author(s):  
Jedidiah Carlson ◽  
Adam E Locke ◽  
Matthew Flickinger ◽  
Matthew Zawistowski ◽  
Shawn Levy ◽  
...  

AbstractA detailed understanding of the genome-wide variability of single-nucleotide germline mutation rates is essential to studying human genome evolution. Here we use ∼36 million singleton variants from 3,560 whole-genome sequences to infer fine-scale patterns of mutation rate heterogeneity. Mutability is jointly affected by adjacent nucleotide context and diverse genomic features of the surrounding region, including histone modifications, replication timing, and recombination rate, sometimes suggesting specific mutagenic mechanisms. Remarkably, GC content, DNase hypersensitivity, CpG islands, and H3K36 trimethylation are associated with both increased and decreased mutation rates depending on nucleotide context. We validate these estimated effects in an independent dataset of ∼46,000 de novo mutations, and confirm our estimates are more accurate than previously published estimates based on ancestrally older variants without considering genomic features. Our results thus provide the most refined portrait to date of the factors contributing to genome-wide variability of the human germline mutation rate.


2020 ◽  
Vol 117 (5) ◽  
pp. 2560-2569 ◽  
Author(s):  
Michael D. Kessler ◽  
Douglas P. Loesch ◽  
James A. Perry ◽  
Nancy L. Heard-Costa ◽  
Daniel Taliun ◽  
...  

De novo mutations (DNMs), or mutations that appear in an individual despite not being seen in their parents, are an important source of genetic variation whose impact is relevant to studies of human evolution, genetics, and disease. Utilizing high-coverage whole-genome sequencing data as part of the Trans-Omics for Precision Medicine (TOPMed) Program, we called 93,325 single-nucleotide DNMs across 1,465 trios from an array of diverse human populations, and used them to directly estimate and analyze DNM counts, rates, and spectra. We find a significant positive correlation between local recombination rate and local DNM rate, and that DNM rate explains a substantial portion (8.98 to 34.92%, depending on the model) of the genome-wide variation in population-level genetic variation from 41K unrelated TOPMed samples. Genome-wide heterozygosity does correlate with DNM rate, but only explains <1% of variation. While we are underpowered to see small differences, we do not find significant differences in DNM rate between individuals of European, African, and Latino ancestry, nor across ancestrally distinct segments within admixed individuals. However, we did find significantly fewer DNMs in Amish individuals, even when compared with other Europeans, and even after accounting for parental age and sequencing center. Specifically, we found significant reductions in the number of C→A and T→C mutations in the Amish, which seem to underpin their overall reduction in DNMs. Finally, we calculated near-zero estimates of narrow sense heritability (h2), which suggest that variation in DNM rate is significantly shaped by nonadditive genetic effects and the environment.


2021 ◽  
Author(s):  
Daniel Melamed ◽  
Yuval Nov ◽  
Assaf Malik ◽  
Michael B. Yakass ◽  
Evgeni Bolotin ◽  
...  

While it is known that the mutation rate varies across the genome, previous estimates of it were based on averaging across various numbers of positions. Here we describe a method to measure the origination rates of target mutations at target base positions and apply it to a 6-bp region in the human β–globin (HBB) gene and to the identical, homologous δ–globin (HBD) region in sperm cells from both African and European donors. The HBB region of interest (ROI) includes the site of the hemoglobin S (HbS) mutation, which protects against malaria, is common in Africa and has served as a classic example of adaptation by random mutation and natural selection. We found a significant correspondence between de novo mutation rates and past observations of alleles in carriers, showing that mutation rates vary substantially in a mutation-specific manner that contributes to the site frequency spectrum. We also found that the overall point mutation rate is significantly higher in Africans than Europeans in the HBB region studied. Finally, the rate of the 20A→T mutation, called the ″HbS mutation″ when it appears in HBB, is significantly higher than expected from the genome-wide average for this mutation type. Nine instances of it were observed in the African HBB ROI, where it is of adaptive significance, representing at least three independent originations, and no instances of it were observed in the European HBB ROI or in the European or African HBD ROI. Further studies will be needed to examine mutation rates at the single-mutation resolution across these and other loci and organisms and to uncover the molecular mechanisms responsible.


Pathogens ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 363
Author(s):  
Sulochana K. Wasala ◽  
Dana K. Howe ◽  
Louise-Marie Dandurand ◽  
Inga A. Zasada ◽  
Dee R. Denver

Globodera pallida is among the most significant plant-parasitic nematodes worldwide, causing major damage to potato production. Since it was discovered in Idaho in 2006, eradication efforts have aimed to contain and eradicate G. pallida through phytosanitary action and soil fumigation. In this study, we investigated genome-wide patterns of G. pallida genetic variation across Idaho fields to evaluate whether the infestation resulted from a single or multiple introduction(s) and to investigate potential evolutionary responses since the time of infestation. A total of 53 G. pallida samples (~1,042,000 individuals) were collected and analyzed, representing five different fields in Idaho, a greenhouse population, and a field in Scotland that was used for external comparison. According to genome-wide allele frequency and fixation index (Fst) analyses, most of the genetic variation was shared among the G. pallida populations in Idaho fields pre-fumigation, indicating that the infestation likely resulted from a single introduction. Temporal patterns of genome-wide polymorphisms involving (1) pre-fumigation field samples collected in 2007 and 2014 and (2) pre- and post-fumigation samples revealed nucleotide variants (SNPs, single-nucleotide polymorphisms) with significantly differentiated allele frequencies indicating genetic differentiation. This study provides insights into the genetic origins and adaptive potential of G. pallida invading new environments.


Author(s):  
Jhons Fatriyadi SUWANDI ◽  
Widya ASMARA ◽  
Hari KUSNANTO ◽  
Din SYAFRUDDIN ◽  
Supargiyono SUPARGIYONO

Background: Malaria is an infectious disease caused by Plasmodium sp., that still prevalence in some part of Indonesia. District of Pesawaran is one of malaria endemic area in the Province of Lampung. The purpose of this study was to evaluate the efficacy of the ACT treatment in the District of Pesawaran Province of Lampung, Indonesia from Dec 2012 to Jul 2013 and the genetic variation of the Plasmodium falciparum also studied. Methods: This study was observational analytic study of falciparum malaria patients treated with ACT and primaquine (DHP-PQ and AAQ-PQ) at Hanura Primary Health Centre (Puskesmas). DNA isolation was done with QIAmp DNA Mini Kit. Amplification of PfMDR1, MSP1, and MSP2 genes was done with appropriate forward and reverse primer and procedures optimized first. PCR Product of PfMDR1 gene was prepared for sequencing. Data analysis was done with MEGA 6 software. Results: The results of this research are DHP-PQ effectiveness was still wellness among falciparum malaria patients in District of Pesawaran, Province of Lampung, Indonesia. There is Single-nucleotide mutation of N86Y of PfMDR1 gene. The dominant alleles found are MAD20 and 3D7 alleles with Multiplicity of Infection (MOI) are low. Conclusion: Therapy of DHP-PQ as an antimalarial falciparum in Pesawaran District, Lampung, Indonesia is still good. The genetic variation found was the SNP on the N86Y PfMDR1 gene, with dominant allele MAD20 and 3D7.


Author(s):  
Philippe Henry

In the present research, I used an open access data set (Medicinal Genomics) consisting of nearly 200'000 genome-wide single nucleotide polymorphisms (SNPs) typed in 28 cannabis accessions to shed light on the plant's underlying genetic structure. Genome-wide loadings were used to sequentially cull less informative markers. The process involved reducing the number of SNPs to 100K, 10K, 1K, 100 until I identified a set of 42 highly informative SNPs that I present here. The two first principal components, encompass over 3/4 of the genetic variation present in the dataset (PCA1 = 48.6%, PCA2= 26.3%). This set of diagnostic SNPs is then used to identify clusters into which cannabis accession segregate. I identified three clear and consistent clusters; reflective of the ancient domestication trilogy of the genus Cannabis.


2020 ◽  
Author(s):  
Markus Pfenninger ◽  
Halina Binde Doria ◽  
Jana Nickel ◽  
Anne Thielsch ◽  
Klaus Schwenk ◽  
...  

AbstractMutations are the ultimate source of heritable variation and therefore the fuel for evolution, but direct estimates exist only for few species. We estimated the spontaneous nucleotide mutation rate among clonal generations in the waterflea Daphnia galeata with a short term mutation accumulation approach. Individuals from eighteen mutation accumulation lines over five generations were deep genome sequenced to count de novo mutations that were not present in a pool of F1 individuals, representing the parental genotype. We identified 12 new nucleotide mutations in 90 clonal generational passages. This resulted in an estimated haploid mutation rate of 0.745 x 10-9 (95% c.f. 0.39 x 10-9 − 1.26 x 10-9), which is slightly lower than recent estimates for other Daphnia species. We discuss the implications for the population genetics of Cladocerans.


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