Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Recessive”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 505 records · Page 28Linked to original sources
PubMed2006

Fine mapping of the recessive genic male-sterile gene (Bnms1) in Brassica napus L.

A recessive genic male sterility (RGMS) system, S45 AB, has been developed from spontaneous mutation in Brassica napus canola variety Oro, and is being used for hybrid cultivar development in China. The male sterility of S45 was controlled by two duplicated recessive genes, named as Bnms1 and Bnms2. In this study, a NIL (near-isogenic line) population from the sib-mating of S45 AB was developed and used for the fine mapping of the Bnms1 gene, in which the recessive allele was homozygous at the second locus. AFLP technology combined with BSA (bulked segregant analysis) was used. From a survey of 2,560 primer combinations (+3/+3 selective bases), seven AFLP markers linked closely to the target gene were identified, of which four were successfully converted to sequence characterized amplified region (SCAR) markers. For further analysis, a population of 1,974 individuals was used to map the Bnms1 gene. On the fine map, Bnms1 gene was flanked by two SCAR markers, SC1 and SC7, with genetic distance of 0.1 cM and 0.3 cM, respectively. SC1 was subsequently mapped on linkage group N7 using doubled-haploid mapping populations derived from the crosses Tapidor x Ningyou7 and DH 821 x DHBao 604, available at IMSORB, UK, and our laboratory, respectively. Linkage of an SSR marker, Na12A02, with the Bnms1 gene further confirmed its location on linkage group N7. Na12A02, 2.6 cM away from Bnms1, was a co-dominant marker. These molecular markers developed from this research will facilitate the marker-assisted selection of male sterile lines and the fine map lays a solid foundation for map-based cloning of the Bnms1 gene.

Alleles↗
PubMed2004

Genome-wide analysis of defense-responsive genes in bacterial blight resistance of rice mediated by the recessive R gene xa13.

Defense responses triggered by dominant and recessive disease resistance (R) genes are presumed to be regulated by different molecular mechanisms. In order to characterize the genes activated in defense responses against bacterial blight mediated by the recessive R gene xa13, two pathogen-induced subtraction cDNA libraries were constructed using the resistant rice line IRBB13--which carries xa13--and its susceptible, near-isogenic, parental line IR24. Clustering analysis of expressed sequence tags (ESTs) identified 702 unique expressed sequences as being involved in the defense responses triggered by xa13; 16% of these are new rice ESTs. These sequences define 702 genes, putatively encoding a wide range of products, including defense-responsive genes commonly involved in different host-pathogen interactions, genes that have not previously been reported to be associated with pathogen-induced defense responses, and genes (38%) with no homology to previously described functional genes. In addition, R-like genes putatively encoding nucleotide-binding site/leucine rich repeat (NBS-LRR) and LRR receptor kinase proteins were observed to be induced in the disease resistance activated by xa13. A total of 568 defense-responsive ESTs were mapped to 588 loci on the rice molecular linkage map through bioinformatic analysis. About 48% of the mapped ESTs co-localized with quantitative trait loci (QTLs) for resistance to various rice diseases, including bacterial blight, rice blast, sheath blight and yellow mottle virus. Furthermore, some defense-responsive sequences were conserved at similar locations on different chromosomes. These results reveal the complexity of xa13-mediated resistance. The information obtained in this study provides a large source of candidate genes for understanding the molecular bases of defense responses activated by recessive R genes and of quantitative disease resistance.

Chromosomes, Plant↗
PubMed2002

Chloride channel 7 (CLCN7) gene mutations in intermediate autosomal recessive osteopetrosis.

Osteopetrosis is a heterogeneous group of inherited disorders that includes a malignant autosomal recessive form, an intermediate autosomal recessive form and autosomal dominant forms of the disease. Most malignant osteopetroses have been ascribed to mutations in the OC116 gene encoding the human a3 subunit of vacuolar H(+)-ATPase. Few cases of autosomal recessive malignant osteopetrosis have been ascribed to mutations in the chloride channel 7 gene (CLCN7), which accounts for all autosomal dominant type II cases reported to date. Up until now, however, nothing has been known regarding the molecular basis of the intermediate form of osteopetrosis (IARO). Our study of two Portuguese IARO families shows that homozygosity for ClCN7 mutations also accounts for this form of osteopetrosis. The two patients presented with spontaneous fractures in the first years of life and generalised increase of bone density. Direct sequencing of the ClCN7 gene in both patients revealed homozygosity for two mutations (G203D and P470Q). We conclude therefore that ClCN7 mutations not only account for some dominant and malignant forms but also for intermediate forms of osteopetrosis.

Alleles↗
PubMed1999

Dopa-responsive dystonia induced by a recessive GTP cyclohydrolase I mutation.

GTP cyclohydrolase I (GTPCH) catalyzes the rate-limiting step of tetrahydrobiopterin (BH4) biosynthesis. GTPCH has been associated with two clinically distinct human diseases: the recessive hyperphenylalaninemia (HPA) and the dominant dopa-responsive dystonia (DRD). We found a recessive GTPCH mutation (R249S, 747C-->G in a dystonia patient. Her PHA-stimulated mononuclear blood cells had a normal amount of GTPCH mRNA, but low GTPCH activity. Arginine 249 is located at the C-terminus of GTPCH, outside the catalytic site. E. coli expressed recombinant R249S mutant protein possessed normal enzyme activity and kinetics. However, in transfected eukaryotic cells, R249S mutant protein expression level was lower than the wild-type protein. Therefore, this is suspected to be a destabilizing mutation. Our data suggest that DRD could be either dominantly or recessively inherited, and the inheritance might be determined by the mechanism of mutation.

Amino Acid Substitution↗
PubMed2006

Is autosomal recessive deafness associated with oculocutaneous albinism a "coincidence syndrome"?

Hearing impairment is frequently found associated with pigmentary disorders in many syndromes. However, total oculocutaneous albinism (OCA) associated with deafness has been described only once, by Ziprkowski and Adam (Arch Dermatol 89:151-155, 1964) in an inbred family. A syndrome associating deafness and OCA was suggested by the authors, but two separate recessive genes segregating in this inbred group were also proposed later by Fraser (OMIM # 220900). Combined deafness and total OCA were also observed by us in a family originally reported to be nonconsanguineous but in which haplotyping showed evidence of a common ancestry: the proband was affected by both diseases, one of his sisters had only OCA and another sister had only deafness. Both the proband and his deaf sister were found to be homozygotes for the 35delG mutation (GJB2 gene), the most frequent cause of hereditary deafness. Linkage analysis with markers close to the four known OCA loci excluded linkage to OCA1, OCA2, and OCA3, and homozygosity in markers near OCA4 locus was observed. Sequencing of the corresponding gene (MATP) revealed a c.1121delT mutation, which leads to a stop codon at position 397 (L374fsX397). Clearly, the combined occurrence of deafness and albinism in this pedigree was due to mutations in two different genes, showing autosomal recessive inheritance. We speculate that the putative syndrome reported by Ziprkowski and Adam might have resulted from the co-occurrence of autosomal recessive deafness and albinism in the same pedigree, as suggested by Fraser.

Adolescent↗
PubMed2006

A novel missense mutation in MSX1 underlies autosomal recessive oligodontia with associated dental anomalies in Pakistani families.

Tooth agenesis constitutes the most common anomaly of dental development in humans. In the majority of familial cases of hypodontia alone or in association with other anomalies, the mode of inheritance is autosomal dominant. In the present study, we have identified two distantly related consanguineous Pakistani kindreds with an autosomal recessive form of oligodontia with associated dental anomalies. Locus in this case has been mapped on chromosome 4p16.1-p16.3. The maximum two-point LOD score of 2.85 (theta=0.0) was obtained at markers D4S2925 and D4S2285. A maximum multipoint LOD score exceeding 4 was obtained at the same markers. Recombination events observed in affected individuals localized the disease locus between markers D4S412 and D4S2935, spanning a 9.24-cM region on chromosome 4p16.1-p16.3. Sequence analysis of candidate gene MSX1 revealed a novel recessive missense mutation resulting in substitution of alanine to threonine amino acid (p. A219T), located in the MSX1 homeodomain, which is important for DNA binding and protein-protein interaction. The mutation, p. A219T, is the first recessive mutation identified in MSX1.

Anodontia↗
PubMed1975

Concentration-effect studies with MMS, TEB, 2, 4, 6-TriCl-PDMT, and DEN on the induction of dominant and recessive lethals, chromosome loss and translocations in Drosophila sterm.

Comparative tests were made with four mutagens, treating male germ cells, particularly mature sperm, of Drosophila melanogaster. Dominant lethals, sex-linked recessive lethals, sex-chromosome loss and partial loss, and in one test translocations were used as genetic and points. The four mutagens, methanesulphonate (MMS), 2,3,5,6-tetraethyleneimino-I,4-benzoquinone (TEB), I(2,4,6-trichlorophenyl)-3,3-dimethyltriazene (2,4,6-triC1-PDMT), and diethyl nitrosamine (DEN) are known to differ in their chemical properties and mode of mutagenic action. An apparent relationship between dominant lethal induction and other genetic damage was found only with TEB. All four mutagens are efficient inducers of sex-linked recessive lethals. At low concentrations there was no direct concentration-frequency relationships. The two direct mutagens, MMS and TEB were effective in the chromosome loss tests. DEN does not induce translocations or any of the other types of damage studied which can be attributed to chromosome breakage. It is concluded that the sex-linked recessive lethal test is a simple and efficient way of preliminary screening chemical mutagens with Drosophila melanogaster.

Animals↗
PubMed1975

Mutagenic activity of cyclophosphamide, trofosfamide, and ifosfamide in drosophila melanogaster. specific induction of recessive lethals in the absence of detectable chromosome breakage.

The mutagenicity of cyclophosphamide (EndoxanR), trofosfamide (IxotenR), and ifosfamide was tested on male germ cells, mainly mature sperm, of Drosophila melanogaster. The genetic end points used were sex-linked recessive lethals, dominant lethals, sex chromosome loss, and partial Y chromosome loss. For recessive sex-linked lethals, all three substances induced a significant increase over the control. The effectiveness was not concentration dependent. None of the compounds induced dominant lethals, or complete or partial loss of the sex chromosome. The results are interpreted to indicate the existence of a rate-limiting factor which acts as restriction on the amount of active metabolite in the target cell. This amount is considered to be lower than that required to cause a detectable increase in chromosome breakage types of damage, but is detectable with the higher resolving power of the recessive lethal test.

Animals↗
PubMed1976

X-ray-induced recessive lethal mutations in the mouse.

A test of X-ray-induced recessive lethal mutations in mouse spermatogonia (500 rad) was carried out. The test was based on familial analysis, which allowed division on the P pairs into those with lethal heterozygous members and in others assumed to be lethal-free. The F1 males from the latter group, in back-crosses to their daughters, gave an excessive rate of intra-uterine death in comparison with lethal-free males. The excessive death is assumed to reflect the rate of new (induced + spontaneous) recessive lethals or rather lethal equivalents. Three ways of estimating the rate of new recessive lethal mutations gave a mean of 5.5% per genome. From the previous tests we can assume that 1% are spontaneous mutations. Thus the data indicate that the mutation rate per rad per gamete is 9 X 10(-5). This value is identical with a previous estimate. The results are discussed in relation to population tests performed in the early 60's. It is concluded that the lack of observable deterioration in the populations after several consecutive generations of exposure is in accord with the estimates in the present analysis which are more than an order of magnitude lower than assumed at the start of the population tests. It is also stressed that species with different DNA contents show similarities in point estimates of doubling dosages.

Animals↗
PubMed1978

Molecular dosimetry of the mutagen ethyl methanesulfonate in Drosophila melanogaster spermatozoa: linear relation of DNA alkylation per sperm cell (dose) to sex-linked recessive lethals.

The dosage-response curve for EMS was determined with dose measured as ethylations of DNA per sperm cell, and response measured as the relative frequency of sex-linked recessive lethals induced in sperm cells of Drosophila melanogaster. Dose can be converted to ethylations per nucleotide of DNA by dividing ethylations of DNA per sperm cell by 3 X 10(8) nucleotides per sperm cell. Adult males were exposed to equal amounts of either [3H]EMS for determining dose or nonlabeled EMS for determining mutational response. By feeding EMS for 24 h in a concentration of 25 mM, a high dose of 1.4 X 10(-2) ethylations per nucleotide was observed. With 1.4% of the nucleotides ethylated, 57% of the X-chromosomes were hemizygously viable; therefore, ethylation per se is not very efficient in inducing mutations. The relative frequency of mutations increased linearly with the dose from a dose of 2.1 X 10(-4) to 1.4 X 10(-2) ethylations per nucleotide. No threshold was apparent, and the statistical limits of the exponent, 1.0 +/- 0.1, excluded an exponent as high as 1.2. This linear relation suggests no change in mechanism of mutagenesis occurs from low to high dose in Drosophila. A nonlinear relation was found between exposure and dose; when exposure was increased by a factor of 250 (from 0.1 to 25 mM EMS in the feeding medium) dose was increased by a factor of only 68. By extrapolating down from our lowest dose of 2.1 X 10(-4) ethylations per nucleotide with an observed frequency of 0.55% +/- 0.08% sex-linked recessive lethals, we estimate the doubling dose for sex-linked recessive lethals to be 4 X 10(-5) ethylations per nucleotide.

Alkylating Agents↗
PubMed1978

Dominant and recessive effects of induced-lethals in female mice by exposure to gamma-irradiation during the 10th to 14th day of intrauterine life.

The frequency of (dominant and) recessive lethal mutations induced by 160-rad chronic gamma-irradiation given with a dose rate of 0.03 rad/min during the 10th to 14th day of gestation has been studied in female CBA-mice. An increased rate of recessive lethal equivalents by about 10% has been noted. This increase corresponds to a mutation rate of 6.3 X 10(-4) mutation/rad/genome. There were not found any dominant mutations, nor any dominance effects from the induced recessive lethal equivalents. The hazards after irradiation during foetal development are discussed.

Animals↗
PubMed1985

Codominant and recessive 9-beta-D-arabinofuranosyladenine-resistant mutations of baby hamster cells.

9-beta-D-Arabinosyladenine (araA)-resistant mutants of baby hamster kidney (BHK) cells can be classified into 3 classes. In order to gain a better understanding of the mechanism(s) of resistance and the biochemical basis of cytotoxicity of various purine nucleosides, cell hybrids of the mutant and wild-type cells were made and analyzed. The class I araA-resistant, adenosine-kinase-deficient (AK-) allele was shown to be recessive to the wild-type araA-sensitive (AK+) gene. The class II mutant allele, which encodes an altered ribonucleoside diphosphate reductase, was shown to be codominant. The class III mutants show multiple phenotypes, araAr/dAdor/adenosine sensitive (Ados) and alteration in AK activity. The araA- and dAdo-resistant alleles of araS10d, ara-16c, and ara-19a in class III mutant/wild-type hybrid cells are all recessive to the wild-type allele, consistent with a common mechanism of resistance. In contrast the Ados allele of ara-S10d is dominant while those of ara-16c and ara-19a are recessive. The difference may be a reflection of two distinct mechanisms of enhanced Ado sensitivity or, alternatively, it suggests that the sensitivity of the hybrids to Ado is highly dependent on the level of AK activity.

Adenosine Kinase↗
PubMedDate not supplied

Distribution of MR-induced sex-linked recessive lethal mutations in Drosophila melanogaster.

In the 'doubling-dose' method currently used in genetic risk evaluation, two principle assumptions are made and these are: (1) there is proportionality between spontaneous and induced mutations and (2) the lesions that lead to spontaneous and induced mutations are essentially similar. The studies reported in this paper were directed at examining the validity of these two assumptions in Drosophila. An analysis was made of the distribution of sex-linked recessive lethals induced by MR, one of the well-studied mutator systems in Drosophila. Appropriate genetic complementation tests with 15 defined X-chromosome duplications showed that MR-induced lethals occurred at many sites along the X-chromosome (in contrast to the known locus specificity of MR-induced visible-mutations); some, but not all these sites at which recessive lethals arose in the MR-system are the same as those known to be hot-spots for X-ray-induced lethals. With in situ hybridization we were able to demonstrate that a majority of MR-induced lethals is associated with a particular mobile DNA sequence, the P-element, i.e. they arose as a result of transposition. The differences between the profiles of MR-induced and X-ray-induced recessive lethals, and the nature of MR-induced and X-ray-induced mutations, thus raise questions about the validity of the assumptions involved in the use of the 'doubling-dose' method.

Animals↗
PubMed1990

I-R hybrid dysgenesis in Drosophila melanogaster: nature and site specificity of induced recessive lethals.

This paper presents results of the genetic and cytological analysis of 144 sex-linked recessive lethals, plus 1 non-lethal. All of them were induced by I-R hybrid dysgenesis. This collection of mutants was pooled from experiments involving inducer chromosomes that differ in the chromosomal position of their I elements. Our results show that 30% of the recessive lethals are associated with chromosomal rearrangements which depend on the strength of the I-R interaction. These lethals are induced on both inducer- and reactive-origin chromosomes, and their frequency is dependent on the structure of the inducer chromosome used. The I-R-induced lethals occur along the entire length of the X chromosome. These sites probably correspond to specific loci which are more or less homologous with I. The complementation relationships showed that some specific loci were more frequently involved in all the lethal mutations tested. The most sensitive loci are, in order of observation: l(1)J1, ct, f, ma1 and m. Among induced recessive lethals considered to be point mutation, complementation tests showed that many of them are in fact multilocus deficiencies which can be detected only at the molecular level. It seems that the production of I-R rearrangements (cytologically visible or not) may be the most important mechanism leading to lethal mutations. These mutations probably occur during the transposition of I elements, hence their importance from an evolutionary standpoint.

Animals↗
PubMed1990

The frequency of dominant cataract and recessive specific-locus mutations and mutation mosaics in F1 mice derived from post-spermatogonial treatment with ethylnitrosourea.

The frequency of dominant cataract and recessive specific-locus mutations and mutation mosaics was determined in F1 mice derived from post-spermatogonial germ-cell stage treatment with 2 X 80, 160 or 250 mg/kg ethylnitrosourea. A total of 5 dominant cataract mutations, 3 dominant cataract mutation mosaics, 1 specific-locus mutation and 9 specific-locus mutation mosaics were recovered in 15,542 screened F1 offspring. Results indicate that ethylnitrosourea treatment increases the mutation rate of dominant cataract and recessive specific-locus alleles in post-spermatogonial germ-cell stages of the mouse and that the mutations occur mainly as mosaics. Genetic confirmation of newly induced mutations occurring as mosaics is more problematical for induced recessive alleles than for induced dominant alleles and should be considered when evaluating such mutagenicity results.

Alleles↗
PubMed1993

The induction of recessive mutations in mouse primordial germ cells with N-ethyl-N-nitrosourea.

A specific-locus test was carried out to examine the mutagenic activity of N-ethyl-N-nitrosourea (ENU) on mouse primordial germ cells (PGC). Embryos of C3H/He mice were treated transplacentally with 30 or 50 mg ENU per kg of maternal body weight on day 8.5, 10.5, or 13.5 of gestation (G8.5 day, G10.5 day, or G13.5 day). Male and female mice that had been treated with ENU in embryonic stages were mated with female or male tester PW mice to detect recessive mutations induced in PGC. ENU induced recessive mutations at a relatively high rate in PGC at these developmental stages. The most sensitive stage was G10.5 day. On G8.5 day, the induced mutation rate in males and females was not significantly different. Cluster mutations, which originate from the limited number of PGC and cell killing, were more frequently induced at an earlier developmental stage. The induced mutation rate per unit dose of ENU (1 mg/kg) was higher in G8.5 and G10.5 day PGC than in stem-cell spermatogonia. It can be concluded that mouse PGC are more sensitive than stem-cell spermatogonia to the induction of recessive mutations by ENU.

Age Factors↗
PubMed1994

Forward-mutation tests on the antitumor agent ICR-170 in Neurospora crassa demonstrate that it induces gene/point mutations in the ad-3 region and an exceptionally high frequency of multiple-locus ad-3 mutations with closely linked sites of recessive lethal damage.

The mutagenicity of the antitumor agent ICR-170 (2-methoxy-6-chloro-9-[(ethyl-2-chloroethyl)amino propylamino] acridine dihydrochloride) in the adenine-3 (ad-3) region was studied with a two-component heterokaryon (H-12) of Neurospora crassa. The objective was to characterize the genetic damage produced by this acridine nitrogen mustard derivative to determine in a lower eukaryotic organism the basis for its potent activity against ascites tumors in mice. As in higher eukaryotes, specific-locus mutations in the ad-3 region of strain H-12 result from gene/point mutations, multiple-locus mutations, and multilocus deletion mutations at the closely linked ad-3A and ad-3B loci. Six different treatments of conidial suspensions of H-12 with ICR-170 were used to obtain dose-response curves for inactivation of conidia as well as the overall induction of ad-3 forward mutations using a direct method based on pigment accumulation rather than a requirement for adenine. These experiments demonstrated that: (1) the slope of the dose-response curve for ICR-170-induced specific-locus mutations in the ad-3 region was 1.97 +/- 0.02, and (2) ICR-170 is a potent mutagen (maximum forward-mutation frequency between 1000 and 10,000 ad-3 mutations per 10(6) survivors) for the induction of specific-locus mutations in the ad-3 region. Both biochemical and classical genetic tests were used to characterize the ICR-170-induced ad-3 mutations from each of the six treatments to distinguish the different genotypic classes and subclasses. The overall data base demonstrates that ICR-170-induced ad-3 mutations result exclusively from gene/point mutations at the ad-3A and ad-3B loci and not multilocus deletion mutations. In addition, the frequency of multiple-locus ad-3 mutations resulting from gene/point mutations at the ad-3A and ad-3B loci with a separate site of recessive lethal damage elsewhere in the genome increases as a function of dose. However, an exceptionally high frequency of multiple-locus ad-3 mutations consisting of gene/point mutations at the ad-3A and ad-3B loci with a separate site of closely linked recessive lethal damage was found at all doses. Comparison of the dose-response curves for the major classes and subclasses of ICR-170-induced ad-3 mutations demonstrates that the gene/point ad-3 mutations and multiple-locus ad-3 mutations with a separate site of recessive lethal damage elsewhere in the genome have different induction kinetics.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenine↗
PubMed1996

Dose-dependent induction of recessive mutations with N-ethyl-N-nitrosourea in primordial germ cells of male mice.

Using a specific locus test, we previously found that N-ethyl-N-nitrosourea (ENU) induces recessive mutations at a relatively high rate in male mouse primordial germ cells (PGC) at 8.5, 10.5 and 13.5 days of development (G8.5, G10.5 and G13.5). A large difference was observed on the induced mutation rate between 30 and 50 mg/kg ENU in 10.5-day PGC. We therefore carried out specific locus tests to ascertain whether ENU induces recessive mutations in a dose-dependent manner in G8.5 and G10.5 PGC. We also gave multiple doses of 25 mg/kg ENU using an 18-h interval, the approximate doubling time of PGC at these developmental stages, to test for an additive effect on the induced mutations rate. A dose-dependent induction of recessive mutations by ENU was observed in both G8.5 and G10.5 PGC, and multiple dosing of 25 mg/kg ENU showed an additive effect. Comparing these results to data on spermatogonial stem cells, we conclude the capacity to repair ENU-induced premutagenic damages is less effective in male mouse PGC at these developmental stages than in spermatogonial stem cells.

Animals↗