scholarly journals Spatial gene drives and pushed genetic waves

2017 ◽  
Vol 114 (32) ◽  
pp. 8452-8457 ◽  
Author(s):  
Hidenori Tanaka ◽  
Howard A. Stone ◽  
David R. Nelson
Keyword(s):  
Reaction Diffusion ◽  
Two Dimensions ◽  
Wild Type Allele ◽  
Gene Drive ◽  
Wild Type ◽  
Wave Regime ◽  
Spatial Spread ◽  
Type Allele ◽  
Reaction Diffusion Model ◽  
Gene Drives

Gene drives have the potential to rapidly replace a harmful wild-type allele with a gene drive allele engineered to have desired functionalities. However, an accidental or premature release of a gene drive construct to the natural environment could damage an ecosystem irreversibly. Thus, it is important to understand the spatiotemporal consequences of the super-Mendelian population genetics before potential applications. Here, we use a reaction–diffusion model for sexually reproducing diploid organisms to study how a locally introduced gene drive allele spreads to replace the wild-type allele, although it possesses a selective disadvantages> 0. Using methods developed by Barton and collaborators, we show that socially responsible gene drives require 0.5 <s< 0.697, a rather narrow range. In this “pushed wave” regime, the spatial spreading of gene drives will be initiated only when the initial frequency distribution is above a threshold profile called “critical propagule,” which acts as a safeguard against accidental release. We also study how the spatial spread of the pushed wave can be stopped by making gene drives uniquely vulnerable (“sensitizing drive”) in a way that is harmless for a wild-type allele. Finally, we show that appropriately sensitized drives in two dimensions can be stopped, even by imperfect barriers perforated by a series of gaps.

scholarly journals Spatial gene drives and pushed genetic waves

2017 ◽  
Author(s):  
Hidenori Tanaka ◽  
Howard A. Stone ◽  
David R. Nelson
Keyword(s):  
Reaction Diffusion ◽  
Two Dimensions ◽  
Wild Type Allele ◽  
Gene Drive ◽  
Wild Type ◽  
Wave Regime ◽  
Spatial Spread ◽  
Type Allele ◽  
Reaction Diffusion Model ◽  
Gene Drives

Gene drives have the potential to rapidly replace a harmful wild-type allele with a gene drive allele engineered to have desired functionalities. However, an accidental or premature release of a gene drive construct to the natural environment could damage an ecosystem irreversibly. Thus, it is important to understand the spatiotemporal consequences of the super-Mendelian population genetics prior to potential applications. Here, we employ a reaction-diffusion model for sexually reproducing diploid organisms to study how a locally introduced gene drive allele spreads to replace the wild-type allele, even though it posses a selective disadvantages> 0. Using methods developed by N. Barton and collaborators, we show that socially responsible gene drives require 0.5 <s< 0.697, a rather narrow range. In this “pushed wave” regime, the spatial spreading of gene drives will be initiated only when the initial frequency distribution is above a threshold profile called “critical propagule”, which acts as a safeguard against accidental release. We also study how the spatial spread of the pushed wave can be stopped by making gene drives uniquely vulnerable (“sensitizing drive”) in a way that is harmless for a wild-type allele. Finally, we show that appropriately sensitized drives in two dimensions can be stopped even by imperfect barriers perforated by a series of gaps.

scholarly journals CYP2C19 Polymorphisms in Indonesia: Comparison among Ethnicities and the Association with Clinical Outcomes

Biology ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 300
Author(s):  
Muhammad Miftahussurur ◽  
Dalla Doohan ◽  
Ari Fahrial Syam ◽  
Iswan Abbas Nusi ◽  
Phawinee Subsomwong ◽  
...  
Keyword(s):  
Proton Pump Inhibitor ◽  
Clinical Outcomes ◽  
Proton Pump ◽  
Poor Metabolizers ◽  
Wild Type Allele ◽  
Wild Type ◽  
Type Allele ◽  
Sydney System ◽  
Intermediate Metabolizers ◽  
Cyp2c19 Polymorphisms

CYP2C19 polymorphisms are important factors for proton pump inhibitor-based therapy. We examined the CYP2C19 genotypes and analyzed the distribution among ethnicities and clinical outcomes in Indonesia. We employed the polymerase chain reaction-restriction fragment length polymorphism method to determine the CYP2C19 genotypes and evaluated inflammation severity with the updated Sydney system. For CYP2C19*2, 46.4% were the homozygous wild-type allele, 14.5% were the homozygous mutated allele, and 39.2% were the heterozygous allele. For CYP2C19*3, 88.6% were the homozygous wild-type allele, 2.4% were the homozygous mutated allele, and 9.0% were the heterozygous allele. Overall, the prevalence of rapid, intermediate, and poor metabolizers in Indonesia was 38.5, 41.6, and 19.9%, respectively. In the poor metabolizer group, the frequency of allele *2 (78.8%) was higher than the frequency of allele *3 (21.2%). The Papuan had a significantly higher likelihood of possessing poor metabolizers than the Balinese (OR 11.0; P = 0.002). The prevalence of poor metabolizers was lower compared with the rapid and intermediate metabolizers among patients with gastritis and gastroesophageal reflux disease. Intermediate metabolizers had the highest prevalence, followed by rapid metabolizers and poor metabolizers. Dosage adjustment should therefore be considered when administering proton pump inhibitor-based therapy in Indonesia.

Monoallelic Expression of Pax5: A Paradigm for the Haploinsufficiency of Mammalian Pax Genes?

1999 ◽  
Vol 380 (6) ◽  
Author(s):  
S.L. Nutt ◽  
M. Busslinger
Keyword(s):  
Human Disease ◽  
Mouse Genome ◽  
Monoallelic Expression ◽  
Wild Type Allele ◽  
Loss Of Function ◽  
Wild Type ◽  
Type Allele ◽  
Pax Genes ◽  
Default State ◽  
Mammalian Genes

AbstractIt is generally assumed that most mammalian genes are transcribed from both alleles. Hence, the diploid state of the genome offers the advantage that a loss-of-function mutation in one allele can be compensated for by the remaining wild-type allele of the same gene. Indeed, the vast majority of human disease syndromes and engineered mutations in the mouse genome are recessive, indicating that recessiveness is the ‘default’ state. However, a minority of genes are semi-dominant, as heterozygous loss-of-function mutation in these genes leads to phenotypic abnormalities. This condition, known as haploinsufficiency, has been described for five of the nine mammalian

Multiple Congenital Ocular Anomalies in a silver coat Missouri Fox Trotter stallion

2021 ◽  
Vol 49 (05) ◽  
pp. 350-354
Author(s):  
Verena Maria Herb ◽  
Verena Zehetner ◽  
Klaas-Ole Blohm
Keyword(s):  
Missense Mutation ◽  
Coat Color ◽  
Incidental Finding ◽  
Unknown Origin ◽  
Allelic Frequency ◽  
Cystic Lesions ◽  
Wild Type Allele ◽  
Wild Type ◽  
Type Allele ◽  
Phenotype Characterization

AbstractThis is the first description of Multiple Congenital Ocular Anomalies (MCOA) in a silver coat Missouri Fox Trotter determined to be heterozygous for the Silver PMEL17 missense mutation associated with MCOA and a silver coat in other breeds. The stallion was treated for meningoencephalitis and bilateral uveitis of unknown origin. A complete ophthalmic examination and ocular ultrasonography were performed. As an incidental finding, the patient exhibited bilateral cystic lesions restricted to the temporal anterior uvea consistent with the Cyst phenotype and was genotyped heterozygous for the Silver mutation. Additionally, 4 other non-silver colored Missouri Fox Trotters were genotyped homozygous for the wild-type allele. Screening for PMEL17 mutation in Missouri Fox Trotters accompanied by ophthalmic phenotype characterization is recommended to determine the allelic frequency and facilitate informed breeding decisions since the silver coat color is particularly popular.

scholarly journals GENETIC ANALYSIS OF THREE DOMINANT FEMALE-STERILE MUTATIONS LOCATED ON THE X CHROMOSOME OF DROSOPHILA MELANOGASTER

Genetics ◽  
1983 ◽  
Vol 105 (2) ◽  
pp. 309-325
Author(s):  
D Busson ◽  
M Gans ◽  
K Komitopoulou ◽  
M Masson
Keyword(s):  
X Chromosome ◽  
Germ Line ◽  
Female Sterility ◽  
Recessive Mutation ◽  
Wild Type Allele ◽  
Wild Type ◽  
Allelic Series ◽  
Type Allele ◽  
Dominant Female ◽  
Female Germ Line

ABSTRACT Three dominant female-sterile mutations were isolated following ethyl methanesulfonate (EMS) mutagenesis. Females heterozygous for two of these mutations show atrophy of the ovaries and produce no eggs (ovoD  1) or few eggs (ovoD  2); females heterozygous for the third mutation, ovoD  3, lay flaccid eggs. All three mutations are germ line-dependent and map to the cytological region 4D-E on the X chromosome; they represent a single allelic series. Two doses of the wild-type allele restore fertility to females carrying ovoD  3 and ovoD  2, but females carrying ovoD  1 and three doses of the wild-type allele remain sterile. The three mutations are stable in males but are capable of reversion in females; reversion of the dominant mutations is accompanied by the appearance, in the same region, of a recessive mutation causing female sterility. We discuss the utility of these mutations as markers of clones induced in the female germ line by mitotic recombination as well as the nature of the mutations.

scholarly journals Short and sweet: foreleg abnormalities in Havanese and the role of the FGF4 retrogene

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Kim K. L. Bellamy ◽  
Frode Lingaas
Keyword(s):  
Mutant Allele ◽  
Large Degree ◽  
Population Increase ◽  
Wild Type Allele ◽  
Wild Type ◽  
Gradual Decline ◽  
Type Allele ◽  
Population Frequency ◽  
Welfare Implications

Abstract Background Cases of foreleg deformities, characterized by varying degrees of shortened and bowed forelegs, have been reported in the Havanese breed. Because the health and welfare implications are severe in some of the affected dogs, further efforts should be made to investigate the genetic background of the trait. A FGF4-retrogene on CFA18 is known to cause chondrodystrophy in dogs. In most breeds, either the wild type allele or the mutant allele is fixed. However, the large degree of genetic diversity reported in Havanese, could entail that both the wild type and the mutant allele segregate in this breed. We hypothesize that the shortened and bowed forelegs seen in some Havanese could be a consequence of FGF4RG-associated chondrodystrophy. Here we study the population prevalence of the wild type and mutant allele, as well as effect on phenotype. We also investigate how the prevalence of the allele associated with chondrodystrophy have changed over time. We hypothesize that recent selection, may have led to a gradual decline in the population frequency of the lower-risk, wild type allele. Results We studied the FGF4-retrogene on CFA18 in 355 Havanese and found variation in the presence/absence of the retrogene. The prevalence of the non-chondrodystrophic wild type is low, with allele frequencies of 0.025 and 0.975 for the wild type and mutant allele, respectively (linked marker). We found that carriers of the beneficial wild type allele were significantly taller at the shoulder than mutant allele homozygotes, with average heights of 31.3 cm and 26.4 cm, respectively. We further found that wild type carriers were born on average 4.7 years earlier than mutant allele homozygotes and that there has been a gradual decline in the population frequency of the wild type allele during the past two decades. Conclusions Our results indicate that FGF4RG-associated chondrodystrophy may contribute to the shortened forelegs found in some Havanese and that both the wild type and mutant allele segregate in the breed. The population frequency of the wild type allele is low and appear to be decreasing. Efforts should be made to preserve the healthier wild type in the population, increase the prevalence of a more moderate phenotype and possibly reduce the risk of foreleg pathology.

scholarly journals Intragenic deletion of CDH1 as the inactivating mechanism of the wild-type allele in an HDGC tumour

Oncogene ◽  
2003 ◽  
Vol 23 (12) ◽  
pp. 2236-2240 ◽  
Author(s):  
Carla Oliveira ◽  
Joyce de Bruin ◽  
Sérgio Nabais ◽  
Marjolijn Ligtenberg ◽  
Cátia Moutinho ◽  
...  
Keyword(s):  
Wild Type Allele ◽  
Wild Type ◽  
Type Allele ◽  
Intragenic Deletion

scholarly journals A Gene-Targeting Approach Identifies a Function for the First Intron in Expression of the α1(I) Collagen Gene

1998 ◽  
Vol 18 (6) ◽  
pp. 3368-3375 ◽  
Author(s):  
Sheriar G. Hormuzdi ◽  
Risto Penttinen ◽  
Rudolf Jaenisch ◽  
Paul Bornstein
Keyword(s):  
Gene Targeting ◽  
Cultured Cells ◽  
Silent Mutation ◽  
Type I ◽  
Wild Type Allele ◽  
Normal Allele ◽  
Wild Type ◽  
Rnase Protection ◽  
Type Allele ◽  
First Intron

ABSTRACT The role of the first intron of the Col1A1 gene in the regulation of type I collagen synthesis remains uncertain and controversial despite numerous studies that have made use of transgenic and transfection experiments. To examine the importance of the first intron in regulation of the gene, we have used the double-replacement method of gene targeting to introduce, by homologous recombination in embryonic stem (ES) cells, a mutated Col1A1 allele (Col-IntΔ). The Col-IntΔ allele contains a 1.3-kb deletion within intron I and is also marked by the introduction of a silent mutation that created an XhoI restriction site in exon 7. Targeted mice were generated from two independently derived ES cell clones. Mice carrying two copies of the mutated gene were born in the expected Mendelian ratio, developed normally, and showed no apparent abnormalities. We used heterozygous mice to determine whether expression of the mutated allele differs from that of the normal allele. For this purpose, we developed a reverse transcription-PCR assay which takes advantage of the XhoI polymorphism in exon 7. Our results indicate that in the skin, and in cultured cells derived from the skin, the intron plays little or no role in constitutive expression of collagen I. However, in the lungs of young mice, the mutated allele was expressed at about 75% of the level of the normal allele, and in the adult lung expression was decreased to less than 50%. These results were confirmed by RNase protection assays which demonstrated a two- to threefold decrease in Col1A1mRNA in lungs of homozygous mutant mice. Surprisingly, in cultured cells derived from the lung, the mutated allele was expressed at a level similar to that of the wild-type allele. Our results also indicated an age-dependent requirement for the intact intron in expression of the Col1A1 gene in muscle. Since the intron is spliced normally, and since the mutant allele is expressed as well as the wild-type allele in the skin, reduced mRNA stability is unlikely to contribute to the reduction in transcript levels. We conclude that the first intron of the Col1A1 gene plays a tissue-specific and developmentally regulated role in transcriptional regulation of the gene. Our experiments demonstrate the utility of gene-targeting techniques that produce subtle mutations for studies ofcis-acting elements in gene regulation.

Loss of the Wild-Type Allele Contributes to Myeloid Expansion and Disease Aggressiveness in FLT3/ITD Knock-in Mice

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 866-866
Author(s):  
Li Li ◽  
Emily Bailey ◽  
Sarah M Greenblatt ◽  
David Huso ◽  
Donald Small
Keyword(s):  
Median Survival ◽  
Conflicts Of Interest ◽  
Lentiviral Vector ◽  
Point Mutations ◽  
Kinase Domain ◽  
Wild Type Allele ◽  
Wild Type ◽  
Type Allele ◽  
Lower Ratio ◽  
The Impact

Abstract Abstract 866 Activating mutations of FLT3, either in the form of internal tandem duplication (ITD) mutations in the juxtamembrane domain or point mutations in the kinase domain, are one of the most frequent mutations in acute myeloid leukemia (AML). AML patients with FLT3/ITD mutations have poor prognosis. Loss of the wild-type FLT3 allele is associated with even worse prognosis when compared to those FLT3/ITD AML patients with the wild-type FLT3 allele still present. Also, FLT3/ITD patients with a high mutant-to-wild-type ratio have a significantly worse outcome than FLT3/ITD patients with a lower ratio. We have previously reported that heterozygous FLT3wt/ITD “knock-in” mice develop a slowly fatal MPN. In order to study the roles wild-type FLT3 play in the development of leukemia associated with FLT3/ITD mutations, we crossed FLT3wt/ITD mice with themselves or with FLT3 “knockout” (FLT3−/−) mice to obtain hemizygous (FLT3−/ITD) or homozygous (FLT3ITD/ITD) FLT3/ITD mice. Investigating phenotypic differences among them reveals the impact of wild-type FLT3 on the development of MPN resulting from FLT3/ITD mutations, and by extension, the effect on acute leukemia. FLT3−/ITD mice, with the loss of the wild-type allele, displayed a more severe MPN, as evidenced by even larger spleen, higher white blood counts and shorter survival, compared to FLT3wt/ITD mice. FLT3ITD/ITD mice had an even severe MPN compared to the FLT3−/ITD and FLT3wt/ITD mice. Fully transformed leukemia developed in some of the FLT3ITD/ITD (7%, 9/129), but not FLT3wt/ITD or FLT3−/ITD mice, with latency ranging from 139 to 304 days. Compared to FLT3wt/ITD mice, FLT3−/ITD and FLT3ITD/ITD mice displayed a further increase in the fraction of primitive hematopoietic cells, with notable increases in ST-HSCs and MPPs. Phosphorylation of STAT5, one of the key downstream targets for constitutively activated FLT3, was increased in FLT3wt/ITD, FLT3−/ITD and FLT3ITD/ITD mice compared to the wild-type control. FLT3wt/ITD, FLT3−/ITD and FLT3ITD/ITD BM also showed increased PU.1 expression and decreased GATA-1 expression, resulting in the subsequent expansion of granulocytic/monocytic/lymphocytic progenitors and a decrease in megakaryocytic/erythrocytic progenitors. It appears that the extent of myeloproliferation in FLT3/ITD mice correlates with loss of the wild-type allele (FLT3wt/ITD vs. FLT3−/ITD) and with the dose of mutant allele (FLT3−/ITD vs. FLT3ITD/ITD). In order to further explore the potential moderating effect of wild-type FLT3 expression on FLT3/ITD-associated MPN, we transduced wild-type FLT3 (wtFLT3, with the lentiviral vector co-expressing GFP) into lineage-depleted FLT3−/ITD CD45.2 BM cells and injected them into lethally irradiated CD45.1 recipients. When injected with sorted (GFP+) BM, vector alone-transduced GFP+FLT3−/ITD BM recipients died of MPN, with a median survival of 62 days. 100% of the recipients in the other three groups, i.e., those injected with vector alone-transduced GFP+ wild-type BM, wtFLT3-transduced GFP+ wild-type BM or wtFLT3-transduced GFP+ FLT3−/ITD BM, remained viable even after the point in time at which all of the recipients in the vector alone-transduced GFP+FLT3−/ITD group died. Similarly, recipients transplanted with unselected (including GFP+ and GFP− populations) vector alone-transduced FLT3−/ITD BM also died early, with a median survival of 73 days and overt signs of MPN. The percentages of GFP+ and GFP− cells in the BM of the dying recipients were comparable to those shortly after transplantation, indicative of the similar expansion ability of the GFP+ and GFP− populations in the BM. In contrast to the wtFLT3-transduced GFP+FLT3−/ITD BM recipients, which have a very prolonged survival, recipients injected with unselected wtFLT3-transduced FLT3−/ITD BM died of MPN, with a median survival of 91 days. Interestingly, 99% of the BM cells in the BM of the dying recipients were GFP−, demonstrating a proliferative/survival advantage for the FLT3−/ITD cells that had not been successfully transduced with wild-type FLT3. These results suggest that the presence of wild-type FLT3 delays and moderates the development of MPN caused by FLT3/ITD mutations. These results suggest that loss of the wild-type allele contributes to the development of a more severe phenotype. Thus, the wild-type FLT3 allele seemingly functions as a “tumor suppressor” in leukemia harboring FLT3/ITD mutations. Disclosures: No relevant conflicts of interest to declare.

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