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At least 163 records · Page 9Linked to original sources
PubMed1977

Salivary peroxidase (SAPX): genetic modification and relationship to the proline-rich (Pr) and acidic (Pa) proteins.

There is genetic polymorphism of the peroxidase of human saliva, but not of leukocytes. The phenotypes are determined by autosomal inheritance, the phenotype of fast mobility (SAPX 1) being determined by homozygosity for a recessive gene (SAPX1) and the phenotypes of slow mobility (SAPX 2 and SAPX 3) being determined by two different genes, SAPX2 and SAPX3, with completely dominant expression at the same locus. The phenotypes are modified by varying degrees of endogenous proteolysis. The SAPX 2 and SAPX 3 types appear to be genetically controlled modifications of SAPX 1 rather than different primary gene products, because of their completely dominant inheritance, their larger molecular size compared to SAPX 1, and their dissociation with 2-mercaptoethanol to give SAPX 1. The acidic protein type Pa 1 is always found in association with SAPX 2, and an uncommon variant type Pa 2 is associated with SAPX 3. The most likely hypothesis is that the genes Pa1 and Pa2 produce products which modify the SAPX 1 type. When the Pa type is Pa 0, the SAPX phenotype is SAPX 1. Since 2-mercaptoethanol can dissociate the Pa 1 protein into a probable monomeric form, and can dissociate SAPX 2 and SAPX 3 to give SAPX 1, it is probable that Pa 1 and Pa 2 monomers complex with SAPX 1 through disulfide bonds to give SAPX 2 or SAPX 3 types. The frequencies of the genes determining the SAPX types are the same as those for Pa: SAPX1 and Pa0 = 0.787, SAPX2 and Pa1 = 0.208, SAPX3 and Pa2 = 0.005.

Electrophoresis, Polyacrylamide Gel↗
PubMed1975

A theoretical note on sex linkage and race differences in spatial visualization ability.

Evidence on the poorer spatial visualization ability in various Negro populations compared to the white populations and on the direction and magnitude of sex difference in spatial ability relative to other abilities suggests the genetic hypothesis that spatial ability is enhanced by a sex-linked recessive gene and that, since the 20-30 percent admixture of Caucasian genes in American Negroes came mostly from male white ancestors, relatively fewer X-linked than autosomal Caucasian genes were transmitted to the American Negro gene pool. The genetic model as explicitly formulated indicates the kinds of data which could substantiate or disporve the theory, but which do not now exist.

Aptitude↗
PubMed1984

Clinical study of proximal spinal muscular atrophy. Report on 89 cases.

A report on 89 cases of proximal Spinal Muscular Atrophy with observations on the clinical features, criteria of classification and modes of inheritance. The various forms into which SMA is divided probably represent a single disease that may begin at any age and may vary in severity, due, as a rule, to an autosomal recessive gene.

Adolescent↗
PubMed2007

Generation and characterization of low phytic acid germplasm in rice (Oryza sativa L.).

Phytic acid (PA, myo-inositol 1,2,3,4,5,6-hexakisphosphate), or its salt form, phytate, is commonly regarded as the major anti-nutritional component in cereal and legume grains. Breeding of low phytic acid (lpa) crops has recently been considered as a potential way to increase nutritional quality of crop products. In this study, eight independent lpa rice mutant lines from both indica and japonica subspecies were developed through physical and chemical mutagenesis. Among them, five are non-lethal while the other three are homozygous lethal. None of the lethal lines could produce homozygous lpa plants through seed germination and growth under field conditions, but two of them could be rescued through in vitro culture of mature embryos. The non-lethal lpa mutants had lower PA content ranging from 34 to 64% that of their corresponding parent and four of them had an unchanged total P level. All the lpa mutations were inherited in a single recessive gene model and at least four lpa mutations were identified mutually non-allelic, while the other two remain to be verified. One mutation was mapped on chromosome 2 between microsatellite locus RM3542 and RM482, falling in the same region as the previously mapped lpa1-1 locus did; another lpa mutation was mapped on chromosome 3, tightly linked to RM3199 with a genetic distance of 1.198 cM. The latter mutation was very likely to have happened to the LOC_Os03g52760, a homolog of the maize myo-inositol kinase (EC 2.7.1.64) gene. The present work greatly expands the number of loci that could influence the biosynthesis of PA in rice, making rice an excellent model system for research in this area.

Alleles↗
PubMed2000

The high oleate trait in the cultivated peanut [Arachis hypogaea L]. II. Molecular basis and genetics of the trait.

A peanut variety with high oleate content has previously been described. When this high oleate variety was used in breeding crosses, the F2 segregation ratio of high oleate to normal oleate progeny was 3:1 or 15:1 depending on the normal oleate varieties used in the crosses. These data suggested that the high oleate trait is controlled by two recessive genes, and some peanut varieties differ from the high oleate variety by mutations in one gene, while others differ by mutations in two genes. The objective of this study was to understand the molecular nature of the high oleate trait and the various segregation patterns. In the previous paper in this issue, we reported that the level of transcripts expressed by one (ahFAD2B) of two homoeologous genes for oleoyl-PC desaturases in cultivated peanut is significantly reduced in high oleate varieties. In this report, we examined gene expression by RT-PCR/restriction digestion in a cross that shows a one-gene segregation pattern for the high oleate trait. Our data showed that the severely reduced level of ahFAD2B transcript correlates absolutely with the high oleate phenotype in this cross, suggesting that the single gene difference is correlated with the ahFAD2B transcript level. When we tested the enzyme activity of the proteins encoded by ahFAD2A and ahFAD2B by expression of the cloned sequences in yeast, only the ahFAD2B gene product showed significant oleoyl-PC desaturase activity. These data, combined with the observation that ahFAD2A shows a change (D150N) in a residue that is absolutely conserved among other desaturases, raised the possibility that the ahFAD2A in these normal and high oleate lines is a mutant allele. In support of this hypothesis, we found that another ahFAD2A allele in a normal oleate peanut line does not have the D150N change. This peanut line displays a two-gene-segregation pattern for the high oleate trait. In conclusion, our results suggest that a mutation in ahFAD2A and a significant reduction in levels of the ahFAD2B transcript together cause the high oleate phenotype in peanut varieties, and that one expressed gene encoding a functional enzyme appears to be sufficient for the normal oleate phenotype.

Alleles↗
PubMed1997

Inheritance of cleft palate in Italy. Evidence for a major autosomal recessive locus.

Although several studies have demonstrated familial aggregation of nonsyndromic cleft palate (CP), the mode of inheritance still remains uncertain. We report the results of complex segregation analysis performed in families of 357 consecutive newborns affected with nonsyndromic CP (i.e., CP not a component feature of malformation syndrome, sequence or association), and registered in the North East Italy and Emilia Romagna congenital malformation registries in the period 1981-1993. This sample, based on a large number of consecutive births, in a well-defined geographical area, with quality control to detect associated anomalies and malformation syndromes, is independent of the number of affected subjects in the family and of CP severity, fitness, and survival. We have analyzed, using the mixed model, the whole sample of nonsyndromic CP, including isolated (i.e., without other anomalies) CP (CPI) and CP associated with at least one other anomaly (CPA), for which a diagnosis of malformation syndrome was not possible. When nonsyndromic CP (including CPA) are considered in the analysis, there is no heterogeneity between CPA and CPI nor between CP including hard palate (CPH) and CP of the soft palate only (CPS). POINTER and COMDS programs cannot discriminate between alternative genetic models; only the hypothesis of non-genetic transmission is rejected. The COMDS analysis two-locus model, which indicates that a modifier locus (or loci) operates in addition to a single major locus (SML), does not show evidence of better fit than SML, polygenic, and multifactorial models. When the severity parameter (defined as CPH and CPS) is added, CPI and CPA show heterogeneity. Eventually, when the analysis is limited to CPI and includes information on severity, a recessive SML, with low penetrance and determining CPH, provides a significant best fit. To have defined a genetic model for CPI and provided evidence for SML inheritance suggests that genetic linkage studies could be implemented. This conclusion is in agreement with previous studies which showed a significant association between alleles of transforming growth factor alpha and CP only in humans, and that single recessive genes may play a crucial role during palatogenesis in mice as well as in Brittany spaniels. Application of the candidate genes to human CPH families could reveal whether these genes are involved.

Alleles↗
PubMed1987

Unique cell surface phenotypes of proliferating lymphocytes in mice homozygous for lpr and gld mutations, defined by monoclonal antibodies to MRL/Mp-lpr/lpr T cells.

In mice bearing the autosomal recessive gene of either lpr or gld, generalized T-cell proliferation and autoimmunity occurs. The surface antigen profiles of these proliferating cells were analyzed using two-color flow cytometry analysis with two newly established rat monoclonal antibodies (ALP-1, ALP-2) directed to lpr cells. The Lp-1 antigen, defined by ALP-1, is expressed exclusively on approximately one-half of proliferating lpr and gld lymph node cells. The Lp-2 antigen, like B 220, is expressed on 80-90% of lpr and gld lymph node cells, the cells in B-cell lineage and a small population of Ly-2+ T cells from normal mice. Thus, the lpr and gld lymph node cells were classified into three subsets, Lp-1+/Lp-2+, Lp-1-/Lp-2+ and Lp-1-/Lp-2-. After stimulation with Con A or a combination of IL-2 and phorbol ester, a small population of T cells from normal mice became Lp-1+. The same treatment increased Lp-2+/Ly-2+ and induced Lp-2+/L3T4+ T-cell populations. Therefore, it seems likely that these phenotypically unique T cells are generated at some stage during the proliferation and differentiation of certain normal T-cell subpopulations. The aberrant T cells in mice with lpr and gld mutations may even be normal regulatory T cells, if they are not proliferating abnormally.

Animals↗
PubMed1975

An unusual form of spinal muscular atrophy with mental retardation occurring in an inbred population.

Three sibs are described suffering from hereditary non-progressive spinal muscular atrophy with non-progressive mental retardation. One of them had in addition signs of pyramidal tract involvement. Muscular weakness was more pronounced proximally than distally and the neck muscles were severely involved. Th.ey all had small skulls and several associated congenital malformations were observed including syndactyly of the left hand in 1 patient. The patients belong to a small inbred community in the Netherlands. Erythropoietic protoporphyria was also present in the family but segregated independently. This combination of "congenital" mental retardation with "congenital" non-progressive spinal muscular atrophy is believed to represent a new syndrome, caused by a rare recessive gene.

Adult↗
PubMed1976

International collaborative study of the spinal muscular atrophies. Part 2. Analysis of genetic data.

Most of the cases in the present study are of the juvenile onset, proximal form of spinal muscular atrophy. The results of the study indicate that the majority of these cases are due to one or more autosomal recessive genes, with very few being inherited as a dominant trait. Affected individuals very widely in the severity of the disease. When 2 or more sibs are affected, they tend to be similar as regards severity, but there are a substantial number of sibships in which this is not so. The data are consistent with either a single gene, with a wide range of expressivity due to the effects of other genes and/or environmental influences, or 2 or more genes, but with considerable overlap in their expression.

Adolescent↗
PubMed1979

Distal spinal muscular atrophy. A clinical and genetic study of 8 kindreds.

Twelve patients (8 kindreds) with distal SMA are described, and an analysis presented of their clinical and genetic features. Distal SMA accounted for 10% of all patients with SMA in a total population survey of this disease in North-East England. The parental consanguinity rate is high, occurring in 3 of the 8 kindreds reported; the sex ratio was 1.0; the segregation ratio of sibs did not differ from 0.25. Intrafamilial concordance for clinical features of the disease is high. This current data is consistent with a suggested aetiology of two separate autosomal recessive genes. Clinical features are discussed and a review of the literature presented. The disease is only slowly progressive, but one of the genetic types may present with infantile or early juvenile onset; there is no evidence that it shortens life. 50% of cases did not have a normal gait after 4 years of age; 50% could not run after 17 years of age; and 50% could not walk unaided after 28 years of age. Details of prognosis, and principles of genetic counselling in this disease are discussed.

Adolescent↗
PubMed1984

Severe muscular dystrophy in girls.

Twelve girls and 2 boys with severe but not congenital muscular dystrophy were found in a national survey. An autosomal recessive gene is likely to account for most if not all of these cases. The condition differs slightly from X-linked Duchenne muscular dystrophy in showing prominent early toe-walking, a milder course, relatively more weakness of the deltoid muscles, normal intelligence, a normal ECG and a more focal pattern of muscle pathology.

Adolescent↗
PubMed1986

Autosomally inherited recessive spastic ataxia, macular corneal dystrophy, congenital cataracts, myopia and vertically oval temporally tilted discs. Report of a Bedouin family--a new syndrome.

A Bedouin family is described with an unusual form of spinocerebellar degeneration. Spastic ataxia was found to be associated with congenital cataracts, macular corneal dystrophy and non-axial myopia, in the absence of retardation of somatic or mental maturation. Immunological abnormalities were common. Genetic analysis revealed that the pedigree is expressing the transmission and segregation of a single mutant autosomal recessive gene.

Cataract↗
PubMed1975

Development of the obese-hyperglycemic syndrome in mice with a growth hormone deficiency.

By mating mice heterozygous for the recessive gene, obese (ob/+) (+/+), with mice homozygous for the recessive gene, dwarf (+/+)(dw/dw), and subsequent mating of the offspring, mice homozygous for both the obese and dwarf gene were obtained. It was established that the genes for obese and dwarf mice belong to different linkage groups. The homozygous obese dwarf mice develop obesity and hyperinsulinemia. The degree of hyperglycemia developed by these homozygotes is not significantly different from that of nonobese dwarf mice. Because homozygous dwarf mice are deficient in growth hormone production, it was concluded that obesity and hyperinsulinemia can develop under conditions of extreme growth hormone deficiency.

Animals↗
PubMed1988

The effect of the reproductive system on mutation load.

J. B. S. Haldane (Amer. Nat. 71, 337-349, 1937) argued that, in equilibrium populations, the effect of deleterious mutation on average fitness depends primarily on the mutation rate and is independent of the severity of the mutations. Specifically, the equilibrium population fitness is e-microH, where microH is the haploid genomic mutation rate. Here we extend Haldane's result to a variety of reproductive systems. Using an analysis based on the frequency of classes of individuals with a specified number of mutations, we show that Haldane's principle holds exactly for haploid sex, haploid apomixis, and facultative haploid sex. In the cases of diploid automixis with terminal fusion, diploid automixis with central fusion, and diploid selfing, Haldane's principle holds exactly for recessive mutations and approximately for mutations with some heterozygous effect. In the cases of K-ploid apomixis, diploid endomitosis, and haplodiploidy, we show that Haldane's principle holds exactly for recessive lethal mutations. In addition we extend Haldane's result to various mixtures of the above-mentioned reproductive systems. In the case of diploid out-crossing sexuals, we do not obtain an exact analytic result, but present arguments and computer simulations which show that Haldane's result extends to this case as well in the limit as the number of loci becomes large. Although diverse reproductive systems are equally fit at equilibrium, different reproductive systems harbor vastly different numbers of recessive genes at equilibrium and we provide estimates of these numbers. These different numbers of mutations may create transient selective pressures on individuals with reproductive systems different from that of the equilibrium population.

Animals↗
PubMed1986

Lack of reciprocal translocations in carcinomas.

Among the varied structural chromosomal aberrations present in the common forms of carcinoma, reciprocal translocations generally appear to be lacking. Although the breakpoints may be variable, the chromosomal changes nevertheless commonly result in the loss or gain of particular chromosomal segments. The possible implications of these observations are discussed, especially in relation to the thesis that some of the chromosomal changes in cancer cells are important because they lead to the expression of recessive genes.

Carcinoma↗
PubMed1991

Chronic multifocal osteomyelitis, a new recessive mutation on chromosome 18 of the mouse.

Mice with tail kinks and deformities in their lower extremities were observed in a litter of C.D2-Qa-2+N6F15 mice. A mutant line that exhibits this phenotype in 100% of its offspring was established by subsequent breeding. The abnormalities resembled to some degree those found in a human syndrome termed chronic recurrent multifocal osteomyelitis (CRMO). Accordingly, we name the new mutation chronic multifocal osteomyelitis (cmo). Breeding analysis showed that the defect was determined by a single autosomal recessive gene. Restriction fragment length polymorphism (RFLP) analysis of progeny from a backcross between Mus musculus domesticus (CLA) and C.D2-Qa-(2+)-cmo/cmo indicated that the cmo gene resides on mouse Chromosome 18.

Animals↗
PubMed1990

Detection of DNA polymorphisms between two inbred mouse strains--limitations of restriction fragment length polymorphisms (RFLPs).

Type I (insulin-dependent) diabetes in humans is characterized by a T cell mediated destruction of insulin-secreting pancreatic beta cells. This autoimmune response is very similar to that seen in the non-obese diabetic (NOD) mouse strain. Originally bred from the ICR cataract-prone strain, NOD mice spontaneously develop T cell mediated insulitis and type I diabetes by the age of 6 months. Backcross studies with the NOD mouse strain indicate segregation of at least three recessive genes. One of these, Iddm-1, has been shown to be tightly linked to the mouse MHC, H-2 on chromosome 17. Comparative studies with diabetic patients has also shown linkage to human HLA with protective and predisposing haplotypes being present within the population. In this study we have attempted to identify restriction fragment length polymorphisms (RFLPs) between the genomes of the NOD mouse strain and the diabetes-resistant strain C57BL/10. Such polymorphic loci will be used to screen DNAs from backcross animals that are diagnosed diabetic in an attempt to identify probes linked to the non-H2 disease susceptibility genes.

Animals↗