Modification of radiation-induced sex-linked recessive lethal mutation frequency by tocopherol

1982 ◽  
Vol 105 (1-2) ◽  
pp. 73-77 ◽  
Author(s):  
C Beckman ◽  
R.M Roy ◽  
A Sproule

When the sons of irradiated mice are mated to their own daughters, the average size of the ensuing litters will depend on the number of recessive embryonic lethal genes segregating; it can therefore be used to estimate the rate of induction of recessive lethal mutation by the radiation, provided that one can show that any change is not due to dominant sublethals or semisteriles. Data from an experiment in which mouse sperm were exposed to low accumu­lated doses of radium γ -radiation lead to an estimate of one recessive lethal per 300 roentgen. This is 23 times the corresponding rate for Drosophila melanogaster . It may be compared with the results reported by Russell (1952), who found that the rate of induction of recessive visibles per locus in mouse spermatogonia is 15 times the Drosophila rate; and with those of Vendrely (1955), who found that mouse nuclei have 29 times as much desoxyribonucleic acid as Drosophila nuclei. It is suggested that the mouse may have only slightly more genes than Drosophila , but that each may be about 19 times as large and, for this reason, about 19 times as sensitive to radiation-induced mutation. Implications for human radiogenetic studies are discussed.


Genetics ◽  
1979 ◽  
Vol 92 (1) ◽  
pp. 151-160
Author(s):  
H Traut

ABSTRACT When females of Drosophila melanogaster are treated with chemical or physical mutagens, not only in one but also in both of the two homologous X chromosomes of a given oocyte, a recessive sex-linked lethal mutation may be induced. A method is described that discriminates between such "single" and "double mutations." A theory is developed to show how a comparison between the expected and the observed frequency of double mutations yields an indication of the intercellular distribution (random or nonrandom) of recessive lethal mutations induced by mutagenic agents in oocytes and, consequently, of the distribution (homogeneous or nonhomogeneous) of those agents.—Three agents were tested: FUdR (12.5, 50.0 and 81.0,μg/ml), mitomycin C (130.0 μg/ml) and X rays (2000 R, 150 kV). After FUdR feeding, no increase in the mutation frequency usually observed in D. melanogaster without mutagenic treatment was obtained (u=0.13%, namely three single mutations among 2332 chromosomes tested). After mitomycin C feeding, 104. single and three double mutations were obtained. All of the 50 mutations observed after X irradiation were single mutations. The results obtained in the mitomycin C and radiation experiments favor the assumption of a random intercellular distribution of recessive lethal mutations induced by these two agents in oocytes of D. melanogaster. Reasons are discussed why for other types of mutagenic agents nonrandom distributions may be observed with our technique.


1939 ◽  
Vol 127 (847) ◽  
pp. 257-277 ◽  

In a previous communication (Grüneberg 1938), a new recessive lethal mutation has been described in the rat which produces a variety of ano­malies in various parts of the body. It was shown that all these deviations from the normal, including those disturbances which lead to the death of the lethals, are ultimately caused by an anomaly of the cartilage. All the other manifestations of the gene are therefore of a secondary nature. The histology of the abnormal cartilage will be described in the first part of this paper. For the anomaly of the cartilage, no obvious cause could be discovered by morphological means. It was pointed out, however, that this does not necessarily mean that the gene acts primarily on the cartilage. There remained the possibility that the cartilage itself was only secondarily affected by some general physiological condition of the body which pro­duced no other visible changes.


Development ◽  
1975 ◽  
Vol 34 (2) ◽  
pp. 435-449
Author(s):  
A. Droin ◽  
M. L. Beauchemin

‘Immobile’ (im) is a recessive lethal mutation discovered in the F3 of a Xenopus (Xenopus laevis laevis) originating from a mesodermal nucleus of a neurula transplanted into an enucleated egg. The im embryos do not contract after mechanical stimulation nor do they present any spontaneous contraction from the neurula stage onwards. Development proceeds normally during the first days after which deformation of the lower jaw and tail are observed. The im tadpoles die when normal controls are at the feeding stage. Nervous and muscular tissues are histologically normal in the mutant tadpoles; at advanced stages, however, an irregularity in the path of the myofibrils is observed which is especially conspicuous in the electron microscope. Cholinesterases and ATPase are present in the mutant muscles. Parabiosis and chimerae experiments have shown that parabionts and grafts behave according to their own genotype. Cultures of presumptive axial systems with or without ectoderm lead to the conclusion that, first of all, the abnormality is situated in the mesodermal cells and secondly that the first muscular contractions in normal Xenopus laevis are of myogenic origin. The banding pattern of the myofibrils is normal as was shown by obtaining contractions of glycerol extracted im myoblasts with ATP. It seems therefore that in this mutation, the abnormality is situated in the membranous system of the muscular cell, sarcoplasmic reticulum and/or tubular system as is probably the case in the mdg mutation of the mouse.


Development ◽  
1976 ◽  
Vol 36 (2) ◽  
pp. 373-381
Author(s):  
Martha Spiegelman ◽  
Karen Artzt ◽  
Dorothea Bennett

Mouse embryos homozygous for the recessive lethal mutation tw73 show specific defects in trophectoderm shortly after implantation. The trophectoderm and ectoplacental cone fail to form the usual close association with the uterine decidua, and proliferation is markedly reduced. The embryo proper ceases to develop beyond the two-layered stage and degenerates and dies within 5 days of implantation.


Development ◽  
1978 ◽  
Vol 43 (1) ◽  
pp. 71-84
Author(s):  
E. Rittenhouse ◽  
L. C. Dunn ◽  
J. Cookingham ◽  
C. Calo ◽  
M. Spiegelman ◽  
...  

A new autosomal recessive lethal mutation in the mouse designated cartilage matrix deficiency (cmd) is described. Homozygotes are dwarfed, and have abnormally short trunk, limbs, tail and snout, as well as a protruding tongue and cleft palate. The abdomen is distended because the foreshortened rib cage and spinal column forces the liver ventrad from its normal location. Histological and electron microscopic study reveals a deficiency of cartilage matrix in tracheal cartilage and in all cartilagenous bones examined. The syndrome closely resembles the rare lethal condition achondrogenesis, found in human infants, which is also believed to be due to an autosomal recessive gene.


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