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PubMed2006

Stem fasciated, a recessive mutation in sunflower (Helianthus annuus), alters plant morphology and auxin level.

BACKGROUND AND AIMS: Plant lateral organs such as leaves arise from a group of initial cells within the flanks of the shoot apical meristem (SAM). Alterations in the initiation of lateral organs are often associated with changes in the dimension and arrangement of the SAM as well as with abnormal hormonal homeostasis. A mutation named stem fasciated (stf) that affects various aspects of plant development, including SAM shape and auxin level, was characterized in sunflower (Helianthus annuus). METHODS: F1, F2 and F3 generations were obtained through reciprocal crosses between stf and normal plants. For the genetic analysis, a chi2 test was used. Phenotypic observations were made in field-grown and potted plants. A histological analysis of SAM, hypocotyl, epicotyl, stem and root apical meristem was also conducted. To evaluate the level of endogenous indole-3-acetic acid (IAA), a capillary gas chromatography-mass spectrometry-selected ion monitoring analysis was performed. KEY RESULTS: stf is controlled by a single nuclear recessive gene. stf plants are characterized by a dramatically increased number of leaves and vascular bundles in the stem, as well as by a shortened plastochron and an altered phyllotaxis pattern. By histological analysis, it was demonstrated that the stf phenotype is related to an enlarged vegetative SAM. Microscopy analysis of the mutant's apex also revealed an abnormal enlargement of nuclei in both central and peripheral zones and a disorganized distribution of cells in the L2 layer of the central zone. The stf mutant showed a high endogenous free IAA level, whereas auxin perception appeared normal. CONCLUSIONS: The observed phenotype and the high level of auxin detected in stf plants suggest that the STF gene is necessary for the proper initiation of primordia and for the establishment of a phyllotactic pattern through control of both SAM arrangement and hormonal homeostasis.

Flowers↗

PubMed1988

Metabolic predisposition of a novel mutant (LEC rats) to hereditary hepatitis and hepatoma: alterations of the drug metabolizing enzymes.

Previously we established that 'LEC rats' have displayed spontaneous fulminant hepatitis with severe jaundice, which progressed to liver cancer, and a single autosomal recessive gene is responsible for the cause of the diseases. The activities of drug metabolizing enzymes were assayed in livers from LEC and control (LEA) rats at 4 weeks and 3 months before the onset of liver cancer. At 4 weeks the cytochrome P-450 content of the LEC rat livers was 43% of the control (LEA) value. At 3 months the level was 65% of the control. Epoxide hydrolase, gamma-glutamyltranspeptidase and UDP-glucuronyltransferase activities were 2.6-, 6.9- and 2.4-times higher than those in the LEA rats at 4 weeks, respectively, while glutathione S-transferase activity was not significantly different between the two strains. The enzyme changes in the LEC rats are quite similar to those observed in hyperplastic foci and nodules in chemical carcinogenesis of hepatocytes.

Animals↗

PubMed1974

Genetics of chemical induction of conjugation in Paramecium aurella.

Certain stocks of P. aurelia, syngen 8, could not be induced to conjugate in a solution (KCl + acriflavine + calcium-poor conditions) which was effective in inducing conjugation in other species of Paramecium as well as in other stocks of syngen 8. Both stocks could conjugate by interaction with cells of complementary mating type. Breeding analysis shows that each of the two stocks is homozygous for a recessive gene that blocks induction of conjugation by the KCl-acriflavine solution. These two genes are neither allelic nor linked. Analyses of the phenotypes of the two uninducibles and the wild type were carried out by attempting to induce mating in cells of a single mating type by exposing them to detached mating-reactive cilia from cells of complementary mating type and to the KCl-acriflavine solution, either sequentially or simultaneously. The results confirm the conclusions of others that there is at least one unique step in chemical induction not shared with induction by interaction of complementary mating types. But the results also indicate that there is more than one unique step in chemical induction and that the effects of the two genes described here operate during different periods of the hour required for chemical induction.

Acridines↗

PubMedDate not supplied

Recessive inherited doubling of the chicken's uropygial gland papilla.

A new mutation that causes doubling of the uropygial gland (oil gland) papilla is described, and data that demonstrate its inherited basis are presented. This condition, which has been given the name "double oil gland papilla," varies in its expression: some individuals show only an indention of the papilla tip, while others exhibit a complete cleavage of the papilla such that two completely separate papillae project from a single oil gland. The data presented show that a single autosomal recessive gene, dgp, is the main determinant of this trait, but that its expression may also be influenced by background genetic factors as well as sex. Males more frequently are of the extreme doubling expression while females more frequently express the milder indented phenotype. Approximately 4% of mutant females are classified as normal. A linkage test with the rose comb gene showed independent segregation.

Animals↗

PubMedDate not supplied

Short beak: a new autosomal recessive semilethal mutation in Japanese quail.

Short break (SBK) is a new semilethal mutation of Japanese quail (Coturnix japonica). The SBK individuals are characterized externally by short breaks, shanks, and digits. The shank is also thicker than the wild type. The shape of the mutant beak does not show a parrotlike appearance, contrasting with that of other poultry chondrodystrophic mutants reported in the literature. Bones in the fore and hind limbs of the SBK mutant are also shorter than the wild types. The humerus and ulna in the wing are significantly thicker than the wild types. Other bones in the wing and leg show approximately the same thickness as the wild types. The majority of the SBK mutants die at the late embryonic stage. Some chicks can hatch with no assistance, but almost all die around 3 days of age. However, a part of the SBK individuals (5.3%, 8/151) reach sexual maturity and can reproduce. Genetic analyses revealed that the SBK mutation is controlled by an autosomal recessive gene. The proposed gene symbol is sbk. The sbk gene is allelic to the previously reported stumpy-limb (sl) gene that expresses a somewhat similar phenotype to the SBK.

Animals↗

PubMedDate not supplied

Inheritance of egusi seed type in watermelon.

An unusual seed mutant in watermelon (Citrullus lanatus var. lanatus) has seeds with a fleshy pericarp, commonly called egusi seeds. The origin of the phenotype is unknown, but it is widely cultivated in Nigeria for the high protein and carbohydrate content of the edible seeds. Egusi seeds have a thick, fleshy pericarp that appears during the second to third week of fruit development. We studied the inheritance of this phenotype in crosses of normal seeded Charleston Gray and Calhoun Gray with two plant introduction accessions, PI 490383w and PI 560006, having the egusi seed type. We found that the egusi seed type is controlled by a single recessive gene, and the symbol eg was assigned.

Citrullus↗

PubMed1977

Utilization of analogues of riboflavin by the riboflavin-deficient chick embryo.

Detailed studies of the biological activity of several analogues of riboflavin in the riboflavin-deficient chick embryo were undertaken to extend our knowledge of the comparative biochemistry of these flavins. The riboflavin-deficient eggs were produced by hens homozygous for an autosomal recessive gene (rdrd). 7-Ethyl-8-methyl-flavin was found to be an adequate replacement for riboflavin in che chick embryo, a finding which mimics its effect in the riboflavin-deficient rat. 7,8-Diethyl-flavin was found to be an antagonist in the chick embryo as had been found to be true in the rat. 7-Methyl-8-ethyl-flavin can not be used as a replacement for riboflavin in the chick embryo and further, it inhibits the utilization of riboflavin in normal eggs. 7-Methyl-8-ethyl-flavin had been found to be an adequate replacement for riboflavin in the riboflavin-deficient rat. The classes mammalia and aves are clearly different in respect to the utilization of this flavin.

Animals↗

PubMedDate not supplied

A genetic maternal effect on egg surface in Tribolium castaneum.

Females homozygous for an autosomal recessive gene, wd, produce "weird" eggs that are dry when laid. The wd gene has some important population consequences and also provides a very useful example of a genetic maternal effect for laboratory courses.

Animals↗

PubMedDate not supplied

Hereditary chondrodystrophy in the rabbit. Genetics and pathology of a new mutant, a model for metatropic dwarfism.

Thirty-one cases of a new hereditary chondrodystrophy in the rabbit have been shown to be associated with a fully penetrant autosomal recessive gene symbolized cd. The mutant is viable prenatally but does not survive after birth. It differs from the two other inherited chondrodystrophies, dachs and achondroplasia, but is very similar to the metatropic dwarf reported in man.

Animals↗

PubMedDate not supplied

Linkage of the cadmium resistance locus to loci on mouse chromosome 12.

The autosomal recessive gene cdm that confers resistance to cadmium-induced testicular necrosis in certain inbred strains of mice has been mapped on Chromosome 12 near varitint-waddler (Va). A 3-point cross involving Va, cdm, and amylase-1 (Amy-1) indicated the following gene order and approximate distances: Va-8-cdm-17-Amy-1. The cdm locus is the first polymorphic locus to be placed on Chromosome 12.

Animals↗

PubMedDate not supplied

Myelin deficient, a new neurological mutant in the mouse.

A new autosomal recessive gene in mice is described that produces deficiencies in central nervous system myelin and quaking or trembling of the hindquarters during locomotion. Although both behavioral and central nervous system abnormalities resembled those produced by qk, the new mutation was not an allele of qk. We propose that the new mutation should be labeled myelin deficient (symbol, mld).

Alleles↗

PubMedDate not supplied

Hereditary macrostomus in the rabbit: a model for Treacher Collins syndrome, one form of mandibulofacial dysostosis.

Macrostomus in the rabbit was diagnosed externally by the presence of papillae at the corners of the mouth. Internally the effect is on the zygomatic complex and is extremely variable. Inheritance appears to be due to a single autosomal recessive gene with incomplete penetrance. We propose the symbol mst for the gene responsible for this condition. Evidence is presented to suggest that this gene is very likely in linkage group IV. Macrostomus in the rabbit is a model for the Treacher Collins syndrome, one form of mandibulofacial dysostosis in humans.

Animals↗

PubMedDate not supplied

First arch malformation: a new craniofacial mutant in the mouse.

The first arch malformation arising in a BALB/c strain of mice, has been shown to be inherited as a single autosomal recessive gene and is given the provisional gene symbol far. Affected newborns have extensive bony defects of the face and skull, including a cleft secondary palate, and die within 24 hours of birth. Most of the abnormalities occur in bones derived from the first branchial arch and most of the bony derivatives of the first arch are abnormal in the mutant.

Animals↗

PubMedDate not supplied

Sphingomyelinosis, a new mutation in the mouse: a model of Niemann-Pick disease in humans.

A new autosomal recessive gene causing sphingomyelinosis in mice is described. The name sphingomyelinosis is proposed for this mutant with the gene symbol spm. The disease syndrome caused by this gene has been diagnosed as an analogue of Niemann-Pick disease in humans. Affected mice cannot breed. They show neurological symptoms and weight loss beginning from around 7 weeks of age, and die at 12-14 weeks. By 8 weeks of age striking hepatosplenomegaly and marked enlargement of lymph nodes are present. Large areas of the liver and spleen are replaced by clusters of foam cells. Purkinje cells in the cerebellum are severely depleted. The contents of sphingomyelin and free cholesterol in the liver and spleen are markedly elevated. But the brain shows no obvious changes in lipid concentrations. Sphingomyelinase activity is reduced to about 30 percent that of the homozygous normal controls in the liver, 50 percent in the spleen and 70-80 percent in the brain. Heterozygotes are normal in both lipid concentrations and sphingomyelinase activity. The syndrome produced by spm is different in several ways from that produced by fm, which has been reported to cause sphingomyelinosis in mice.

Animals↗

PubMedDate not supplied

Narrow axis: an inherited anomaly of the second cervical vertebra in the rabbit.

Narrow axis, an inherited anomaly resulting in a marked narrowing of the second cervical vertebra, has been observed in strain X/J rabbits. This condition is first recognizable on X rays at 32-33 days gestation. For size comparisons 21 measurements of the first five cervical vertebrae were taken on the skeletons of each of 14 strain X/J animals (7 normal and 7 with narrow axis) and 14 IIIC/J animals for control at two months of age and 27 strain X/J (11 normal and 16 narrow axis) and 14 strain IIIC/J at seven months of age. The primary effect appeared to be a premature fusion of the centrum with its neural arches. Expression is variable. The effect on the posterior articulation of the atlas appeared to be secondary and adaptive. The other cervical vertebrae and the foramen magnum were relatively unaffected. In the 20-year period encompassed in this report, X rays of 3244 rabbits were used for genetic analysis. Inheritance appears to be due to a single autosomal recessive gene with incomplete penetrance. The condition is neither sex-linked nor sex-limited. We propose the symbol nx for the gene responsible for narrow axis in the rabbit.

Animals↗

PubMedDate not supplied

Hemolytic anemia in the mouse. Report of a new mutation and clarification of its genetics.

A new mutation causing spherocytic, hemolytic anemia has been discovered in the house mouse. It is inherited as a single autosomal recessive gene, allelic with both sph and ha, which, in turn, were shown to be allelic with each other. A revised nomenclature for the three apparent alleles is proposed: sph (formerly sph), sphha (formerly ha), and sph2Bc (the new mutation). Like the other murine hemolytic anemias, sph2Bc involves a defect in the red blood cell membrane protein, spectrin.

Alleles↗

PubMedDate not supplied

Hereditary progressive retinal atrophy in the Abyssinian cat.

Progressive retinal atrophy (PRA), a hereditary eye disease leading to blindness, was found in the Abyssinian breed of cat. Sixty-eight cases of a bilateral generalized retinopathy, at different stages of the disease process, were seen in the breed during ophthalmoscopic examinations of cats throughout Sweden during a 2-year period. Forty-five percent of cats aged 2 years or older were affected in the examined group. The earliest case was diagnosed in a 16-month-old cat. At the age of 3-4 years a bilateral retinal atrophy was usually present in affected cats. Genetic analysis indicates that PRA in the Abyssinian cat is caused by an autosomal recessive gene.

Animals↗

PubMedDate not supplied

New mutation causing jaundice in mice.

A new mutant causing jaundice in mice is reported. Allelism tests indicate that it is not allelic with known hemolytic anemia mutants in mice [hemolytic anemia (sphha), jaundiced (ja), normoblastic anemia (nb), and spherocytosis (sph and sph2Be)]. The jaundiced condition appears in young mice at about 24 hours postpartum and is due to a major increase in unconjugated bilirubin in serum compared to normal controls. Adult mutant mice are not jaundiced and bilirubin levels do not differ from normal mice. Adult male mutants have reduced testes size and no viable sperm. Female mutants are fertile but overall maternal performance is reduced as indicated by increased mortality and reduced growth rate of pups. Genetic tests indicate that a single autosomal recessive gene is responsible for the condition. We propose that the mutant be designated hyper-unconjugated bilirubinemia, with the gene symbol hub.

Animals↗