Stadler Genetics Symposia, volume 04, 1972 (MU)
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Contents of volume 4
- PREFACE
- PROGRAM
- CONTENTS
- PARTICIPANTS AT THE FOURTH STADLER GENETICS SYMPOSIUM
- PHOTOGRAPH OF THE SPEAKERS
- AUTOGRAPHS OF THE SPEAKERS
- HERMAN W. LEWIS: TRENDS IN GENETICS RESEARCH -- PROSPECTS FOR DEVELOPMENT
- E. R. SEARS: CHROMOSOME ENGINEERING IN WHEAT
- ROBERT P. WAGNER: EVOLUTION AND GENETIC SIGNIFICANCE OF MITOCHONDRIA
- STEPHEN H. HOWELL: THE BIOCHEMISTRY OF MEIOSIS AND GENETIC RECOMBINATION
- G. F. SPRAGUE: THE GENETICS OF CORN BREEDING
- LEON S. DURE III AND WILLIAM C. MERRICK: THE ROLE OF tRNA IN DEVELOPMENT
- SHELDON C. REED AND V. ELVING ANDERSON: GENETICS OF PSYCHOSES
- CHARLES F. MULLETT: SEVEN (OR TWENTY-SEVEN) AGAINST OBSCURITY OR STILL FURTHER OBSERVATIONS ON TITTLEBATS
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Item Stadler Genetics Symposia, volume 04, 1972 : Preliminaries and back matter(University of Missouri, Agricultural Experiment Station, 1972) Stadler Genetics Symposium (4th : 1972 : Columbia, Missouri)Item Evolution and genetic significance of mitochondria(University of Missouri, Agricultural Experiment Station, 1972) Wagner, Robert P.; Stadler Genetics Symposium (4th : 1972 : Columbia, Missouri)Mitochondria are constituted of two different membrane systems which may well have quite different origins in replication and evolution. It is hypothesized that the outer membrane is entirely derived from cytosol constituents and activities. The inner membrane and contained matrix is derived from an aerobic promitochondrion which was originally a free living procaryote. It became an endosymbiont in an anaerobic host cell which supplied it with the end products of its glycolytic pathway. These the symbiont converted to CO[subscript 2], H[subscript 2]0 and energy through a system homologous to the present day Krebs TCA cycle and the electron transport system. The original endosymbiont lost its cell wall and became a mitochondrion by a gradual process of integration into the host cell. In this process there was transferred to the nucleus of the host cell the genetic material in the form of DNA from the promitochondrion which was involved in the transcription of messenger RNA coding for the soluble components of the inner membrane-matrix system. This class of soluble inner membrane-proteins contains such enzymes as those involved in the synthesis of isoleucine and valine in Neurospora mitochondria, the Krebs TCA cycle enzymes and cytochrome c. These enzymes are apparently all synthesized in the cytosol and transferred to their appropriate positions within the mitochondria. Their functional integration within the inner membrane-matrix is dependent on the structure of the inner membrane. It is probable that most if not all are allotopic proteins. The inner membrane contains insoluble components which must be synthesized within the mitochondria, since they cannot be transported from the cytosol into the mitochondria. The function of the mitochondrial DNA is to transcribe the RNA necessary for the constitution of a mitochondrial-protein biosynthetic system, and perhaps to furnish messenger RNA for the translation of certain proteins in the inner membrane as well as some that may function in the protein biosynthetic system. A minimal amount of DNA must remain within the mitochondrion both for this reason, and possibly also because some of the proteins must be synthesized by translation of RNA simultaneously with its transcription from DNA as occurs in bacteria.Item The genetics of corn breeding(University of Missouri, Agricultural Experiment Station, 1972) Sprague, G. F.; Stadler Genetics Symposium (4th : 1972 : Columbia, Missouri)Hybrid corn has now replaced open-pollinated varieties almost completely. This change-over has been accompanied by a nearly 3-fold increase in U.S. average yields. The genetic basis for corn breeding rests upon classical Mendelian concepts. On this base has been built a quantitative approach which uses variance components to characterize population and environmental effects. Appropriate models permit separation of genetic effects into additive, dominance, and epistatic components and their interactions. Knowledge concerning the relative magnitude of these effects has been used both to provide a more complete genetic understanding of the early procedures used and to develop new, more efficient breeding procedures. This paper attempts a brief historical review of these genetic developments.Item Chromosome engineering in wheat(University of Missouri, Agricultural Experiment Station, 1972) Sears, E. R.; Stadler Genetics Symposium (4th : 1972 : Columbia, Missouri)Three methods have been developed for the transfer of genetic material to wheat chromosomes from alien chromosomes: (i) Use of ionizing radiation to translocate an alien segment. (ii) Induction of homoeologous pairing, which may be followed by crossing over. This is the easiest and usually the most effective method, provided the alien chromosome is sufficiently closely related to one of its wheat homoeologues that frequent pairing can occur. (iii) Exploitation of the tendency of univalent chromosomes to misdivide. Telocentrics resulting from simultaneous misdivision of two univalents have recently been shown to unite and to produce a new chromosome having one arm from each of the univalents.Item Genetics of psychoses(University of Missouri, Agricultural Experiment Station, 1972) Reed, Sheldon C.; Anderson, V. Elving; Stadler Genetics Symposium (4th : 1972 : Columbia, Missouri)The financial burden of the psychoses each year runs into the billions of dollars while the misery to everyone concerned is beyond calculation. It should be self-evident that the genetics of the psychoses is therefore a topic worth much more consideration than it has received. One egg twins are genetically identical but about half of the time when one of the twins has a psychosis the other one does not display it. The difference in expression must be due to environmental causes. However, the fact that identical twins are concordant for a psychosis about 4 times as often as fraternal twins indicates that there is an important genetic basis for the psychoses. The existence of a genetic basis for the psychoses is also demonstrated by a study of the relatives of a psychotic person. This is the major interest of this paper. Any study of the genetics of psychoses is complicated by numerous variables such as different ages of onset for the various disorders, the lower fertility of psychotic males compared with psychotic females, and our finding that the offspring of psychotic mothers have about twice as high a risk of developing a psychosis as do the offspring of psychotic fathers. A large variable category is that of the environment, though no clues emerged from our study as to what aspects of the environment are involved in the onset of the psychoses. The beneficial effects of tranquilizers and other improvements in treatment have reduced the length of time spent in hospitals by psychotic persons and have reduced their disadvantage in reproduction. Our model shows that if for schizophrenia the disadvantage disappeared there could be a maximum 10 per cent increase in the frequency of schizophrenia in the coming generation. However, it is unlikely that present treatments will result in completely normal reproductive rates for psychotic persons. If a completely preventative treatment for the psychoses should be discovered, there should be an increase in the frequencies of the genes for the psychoses. But this undesired increase in the genes for the psychoses would be balanced off by the reduction in the number of persons actually suffering from the miseries of their mental disorder. It is our conclusion that the functional psychoses have an important genetic basis, that it is multigenic and not strikingly different in nature from that for other quantitative genetic traits.