Genomic clones of a wild-type allele and a transposable element-induced mutant allele of the sucrose synthase gene of Zea mays
 L

ABSTRACT A newly induced mutant of Neurospora, when crossed with an ad-3A mutant, produces asci with four viable black and four inviable white ascospores. The survivors always contain the new mutant allele, never ad-3A. The new allele, which is called SK(ad-3A) (for spore killer of ad-3A), is located at or very near the ad-3A locus. —In crosses homozygous for ad-3A, each ascus contains only inviable white ascospores. This defect in ascospore maturation is complemented by the wild-type allele, ad-3A + (crosses heterozygous for ad-3A and ad-3A + produce mainly viable ascospores), but it is not complemented by the new SK(ad-3A) allele (all ad-3A ascospores from crosses heterozygous for SK(ad-3A) and ad-3A are white and inviable). In crosses homozygous for SK(ad-3A) or heterozygous for SK(ad-3A) and ad-3A +, each ascus contains only viable black ascospores. SK(ad-3A) does not require adenine for growth, and forced heterokaryons between SK(ad-3A) and ad-3A grow at wild-type rates and produce conidia of both genotypes with approximately equal frequency. Thus, the action of SK(ad-3A) is apparently restricted to ascospore formation. Possible mechanisms of the action of this new allele are discussed.

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

Canine Medicine and Genetics ◽

10.1186/s40575-020-00097-5 ◽

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.

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Positive control of sulphate reduction in Escherichia coli. The nature of the pleiotropic cysteineless mutants of E. coli K 12

Biochemical Journal ◽

10.1042/bj1100597 ◽

1968 ◽

Vol 110 (3) ◽

pp. 597-602 ◽

Cited By ~ 21

Author(s):

M. C. Jones-Mortimer

Keyword(s):

Escherichia Coli ◽

Mutant Allele ◽

Positive Control ◽

Wild Type Allele ◽

Wild Type ◽

E Coli ◽

Type Allele ◽

K 12 ◽

Sulphite Reductase

1. The function of the wild-type alleles of the pleiotropic mutants cysB and cysE of Escherichia coli was investigated. 2. The wild-type allele cysB+ is dominant to the mutant allele cysB in stable and transient heterozygotes. 3. The wild-type allele cysE+ is dominant to the mutant allele cysE, as predicted. 4. Sulphur-starved cultures of cysB or cysE strains contain less than 0·2nmole of free cysteine/mg. dry wt. 5. Complementation in vitro is not observed between extracts of cysB mutants and mutants lacking sulphite reductase only. 6. A scheme, involving positive control of the enzymes of sulphate activation and reduction, is suggested to account for the control of cysteine biosynthesis.

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THE REGULATION OF WHITE LOCUS EXPRESSION: A DOMINANT MUTANT ALLELE AT THE WHITE LOCUS OF DROSOPHILA MELANOGASTER

Genetics ◽

10.1093/genetics/95.2.341 ◽

1980 ◽

Vol 95 (2) ◽

pp. 341-353

Author(s):

Paul M Bingham

Keyword(s):

Drosophila Melanogaster ◽

Mutant Allele ◽

Chromosomal Rearrangements ◽

Wild Type Allele ◽

Wild Type ◽

Type Allele ◽

Dominant Mutant ◽

White Locus ◽

Somatic Pairing

ABSTRACT A new mutant allele (wDZL)at the white locus of Drosophila melanogaster is dominant to the wild-type allele, but apparently only when the two alleles are synapsed. When chromosomal rearrangements prevent somatic pairing between the two white alleles, wDZL is rendered recessive to wild type. This observation suggests that the dominance of wDZL is sensitive to a synapsis (transvection) effect. On the basis of this and other properties, it is proposed that wDZL causes the repression of transcription of a synapsed w+ allele, but not of a w+ allele elsewhere in the same nucleus. One model to account for this supposes that wDzL produces a repressor of white-locus transcription. This repressor is presumed to be so unstable that other white genes, removed from wDZL but in the same nucleus, are not detectably repressed. These properties may be simply understood if it is assumed that the repressor produced by the wDZL allele is an RNA molecule.

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MULTIPLEX PCR BASED SINGLE NUCLEOTIDE POLYMORPHISMS ANALYSIS OF HBS POINT MUTATION

10.36106/paripex/2702115 ◽

2020 ◽

pp. 1-4

Author(s):

Jignisha S Patel ◽

Jignaben P Naik ◽

Yazdi M Italia

Keyword(s):

Multiplex Pcr ◽

Point Mutation ◽

Sickle Cell ◽

Mutant Allele ◽

Snp Analysis ◽

Wild Type Allele ◽

Wild Type ◽

Single Nucleotide ◽

Type Allele ◽

Cell Carrier

Introduction: Sickle hemoglobin (HbS), an autosomal recessive hemoglobinopathy cause of Sickle cell disease (SCD), is widely sprayed around the globe affecting millions of people . SCD results from single nucleotide polymorphism (SNP) or point mutation causing amino acid substitution from Glutamic acid to Valine leads to sickled shape red blood cells. SNPs can be well studied by using allele-specific amplification (ASA) technique. Aims & Objective: To develop a simple, rapid, easy and accurate genotyping method for SNP analysis of SCD. Materials and methods: By performing different tests, a well characterized sample panel of 150 different types of samples was prepared. From this sample panel DNA was extracted and used for SNP-genotyping of SCD. Specific primers were used for performing monoplex PCR amplification of wild type allele (HbAA) and mutant allele (HbSS) were performed individually. By using the same primers multiplex PCR assay was experimented. Results and conclusion: This is a simple and low cost molecular method for the detection of point mutation and useful tool for the diagnosis of SCD. The entire analysis can be performed in one reaction mixture, which results in higher speed, higher accuracy, and the need for smaller samples. This technique might be of great value for genotyping of homozygous sickle cell patients (SS) and heterozygous sickle cell trait (AS). But we found one discrepancy with double heterozygous (sickle β-thalassaemia) samples. We were not able to differentiate sickle cell carrier state (AS) from the double heterozygous like sickle β-thalassaemia state. So we conclude that for simultaneous detection of thalassaemia along with sickle cell requires addition of more primers specific for thalassaemia mutation. In addition to this when two bands, one for wild type allele and second for mutant allele appears, care must be taken to conclude whether the person is a sickle cell carrier (AS) or having double heterozygous (sickle β-thalassaemia) like condition.

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SELECTIVE ALLELE LOSS IN MIXED INFECTIONS WITH T4 BACTERIOPHAGE

Genetics ◽

10.1093/genetics/73.1.1 ◽

1973 ◽

Vol 73 (1) ◽

pp. 1-11

Author(s):

Wendy C Benz ◽

Hillard Berger

Keyword(s):

Mutant Allele ◽

Deletion Mutants ◽

Mixed Infections ◽

Repair System ◽

Wild Type Allele ◽

Wild Type ◽

Heteroduplex Dna ◽

E Coli ◽

Type Allele ◽

T4 Bacteriophage

ABSTRACT Evidence is presented that when E. coli B is mixedly infected with T4D wild type and rII deletion mutants, the excess DNA of the wild type allele is lost. No loss is seen in mixed infections with rII point mutants and wild type. In similar experiments with lysozyme addition mutants, the mutant allele is lost. We believe these results demonstrate a repair system which removes "loops" in heteroduplex DNA molecules. A number of phage and host functions have been tested for involvement in the repair of the excess DNA, and T4 genes x and v have been implicated in this process.

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O-090 Correcting a PLCζ mutation in the human germ line to overcome hereditary infertility

Human Reproduction ◽

10.1093/humrep/deab125.020 ◽

2021 ◽

Vol 36 (Supplement_1) ◽

Author(s):

B Bekaert ◽

A Boel ◽

M Popovic ◽

P Stamatiadis ◽

S M Chuva de Sousa Lopes ◽

...

Keyword(s):

Loss Of Heterozygosity ◽

Base Pair ◽

Mutant Allele ◽

Germ Line ◽

Wild Type Allele ◽

Fertilization Failure ◽

Wild Type ◽

Type Allele ◽

Synonymous Variant ◽

Repair Template

Abstract Study question Can clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 gene editing result in the correction of a single base pair substitution that causes male infertility? Summary answer CRISPR/Cas9 administration during intracytoplasmic sperm injection (ICSI) leads to correction attempts of mutant phospholipase C zeta (PLCζ), howeverc loss-of-heterozygosity (LOH). What is known already Failed fertilization after ICSI can be caused by mutations in the sperm-related oocyte factor PLCζ which can be overcome by assisted oocyte activation (AOA). In this way, children may inherit the infertility-causing mutation. Mutation transmission can be overcome through CRISPR/Cas9 delivery during ICSI. In previous studies using CRISPR/Cas9 in the human germline for mutation correction, loss-of-heterozygosity (LOH, loss of the allele of one of the parents) was observed. Two different explanations were given, namely partial or complete paternal chromosomal loss or the correction of the mutation by using the maternal wild-type allele instead of the exogeneous supplied repair template. Study design, size, duration We injected a gRNA-Cas9 protein complex to target the PLCζ mutant allele, a repair template harboring the desired nucleotide substitution and an additional synonymous variant to track template usage, together with patient’s sperm. To overcome fertilization failure, AOA was applied during ICSI. After a culture period of maximal 6 days the embryos were collected. At day 3, some embryos were dissociated in individual blastomeres. The extracted DNA was analyzed through different genetic sequencing techniques. Participants/materials, setting, methods Donated sperm of a patient experiencing complete fertilization failure after routine ICSI, harboring a heterozygous base pair substitution in PLCZ1 (c.136-1G>C), was utilized. Sperm was injected in donated in vitro matured oocytes or in vivo matured oocytes containing clusters of smooth endoplasmic reticulum. Next-generation sequencing was used to assess correction potential. Short tandem repeat (STR) and single nucleotide polymorphism (SNP) assays were used to determine whether the sperm contained the mutation and to evaluate LOH. Main results and the role of chance CRISPR/Cas9 injections had no significant impact (p > 0.05) on embryonic development. Due to the heterozygous nature of the mutation, 47% (27/58) of the embryos originated from mutated sperm injection. The CRISPR components showed a high specificity with absence of insertions/deletions in 97% of the embryos originating from wild-type sperm (n = 31). Embryos originating from mutant sperm (n = 27) fall into three categories:(1) 22% showed the untargeted mutant allele, (2) 52% showed additional mutagenesis and (3) 26% showed the wild-type allele, which could be explained by correction. Mosaicism, defined as various editing events, was present in 17% (1), 21% (2) and 71% (3) of the embryos. The low occurrence of the synonymous variant, incorporated in the repair template, suggests that the template is not used during correction attempts. In only 29% (2/7) and 14% (1/7) of the ‘corrected embryos’, respectively long (>18Mb) or medium width LOH (4Mb) was observed through STR analysis. SNP analysis in closer proximity showed in 71% (5/7) of the embryos LOH, even in the absence of LOH through STR, suggesting also the occurrence of short width LOH. These results will be studied in more detail before definitive conclusions can be made. Chromosomal LOH will be studied by ddRADseq. Limitations, reasons for caution The occurrence of mosaicism and LOH might complicate the use of traditional CRISPR/Cas9 in human embryos and should be studied in detail to draw definite conclusions on its potential future use. To this end, genomic data have been produced from both individual blastomeres and whole-embryos which will be further analyzed. Wider implications of the findings Our findings demonstrate caution to use CRISPR/Cas9 to correct mutations in the germ line. They seem to contradict other reports that show predominant lack of mosaicism and presence of long width LOH. A deeper evaluation will be undertaken to define the length and type of LOH in this study. Trial registration number Not Applicable

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DOMINANCE MODIFIERS IN NEUROSPORA CRASSA: PHENOCOPY SELECTION AND INFLUENCE ON CERTAIN ASCUS MUTANTS

Genetics ◽

10.1093/genetics/71.2.233 ◽

1972 ◽

Vol 71 (2) ◽

pp. 233-245

Author(s):

Peter J Russell ◽

Adrian M Srb

Keyword(s):

Neurospora Crassa ◽

Mutant Allele ◽

Detectable Effect ◽

Wild Type Allele ◽

Wild Type ◽

Group V ◽

Type Allele ◽

Dominance Relationships ◽

Mutant Strains ◽

Dominant Peak

ABSTRACT When homozygous in zygotes, mutant alleles at the peak locus in linkage group V of Neurospora crassa initiate aberrant asci that are nonlinear, in contrast to the linear asci characteristic of wild type. Most mutant alleles are recessive, inasmuch as crosses of the mutant strains with wild type give linear asci. However, five different mutant alleles, when heterozygous with the wild-type allele, act in varying degrees as zygote dominants, initiating both linear and nonlinear asci, the relative proportions depending on the allele. Five modifiers that act on the dominance relationships of at least one of the five possible heterozygotes of a dominant peak and its wild-type allele have been characterized, four of them having been obtained by selection directed against a phenocopy of these mutants induced by treatment of wild type with l-sorbose. The pattern of modifier specificity observed among the various dominant peak heterozygotes indicates that the phenotypic effects are produced by a complex relationship between the modifiers and the dominant peak alleles in relation to their wild-type allele. In all but two cases the direction of modification, where present, is towards decreasing the dominance of the mutant allele in the heterozygote, evidenced by an increase in the percentage of linear asci when compared with control data. The modifiers exert their maximum modification when they themselves are heterozygous with their wild-type alleles and when the dominant peak allele is heterozygous with its wild-type allele. No modification occurs when heterozygous modifiers are included in zygotes homozygous for a dominant peak allele, reinforcing the notion that the modifiers act on the dominance relationship existent between a dominant peak allele and its wild-type allele, rather than influencing some activity of the mutant allele itself. The modifiers have no detectable effect of their own on ascus morphology, since homozygous modifier zygotes initiate entirely linear asci when only wild-type alleles of peak are present in the zygotes. Their only detectable effect, other than dominance modification, appears to be in conferring sorbose resistance to the mycelium. The modifiers are unlinked to the peak locus, and, except for two of them, they are nonallelic.

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Genetics of Glossina morsitans morsitans (Diptera: Glossinidae). X. A mutant (sabr) having long scutellar apical bristles in females

Canadian Journal of Genetics and Cytology ◽

10.1139/g84-122 ◽

1984 ◽

Vol 26 (6) ◽

pp. 770-775 ◽

Cited By ~ 1

Author(s):

R. H. Gooding

Keyword(s):

Linkage Group ◽

Mutant Allele ◽

Glossina Morsitans Morsitans ◽

Wild Type Allele ◽

Wild Type ◽

Glossina Morsitans ◽

Malic Dehydrogenase ◽

Group Iii ◽

Type Allele

A line of Glossina morsitans morsitans Westwood was established in which females have scutellar apical bristles approximately three times as long as normal. In other respects the flies appear normal. The mutant allele, sabr, is recessive to the wild-type allele. The locus for sabr is located in linkage group III, 50 or more map units from the locus for malic dehydrogenase. Scutellar apical bristles in mutant flies are longer in flies emerging from puparia maintained at 30 °C than in flies emerging from puparia maintained at 25 °C.Key words: Glossina, mutation sabr, bristle length.

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

Biology ◽

10.3390/biology10040300 ◽

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.

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