Stadler Genetics Symposia, volume 09, 1977 (MU)

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https://hdl.handle.net/10355/66520

Contents of volume 9

Acknowledgements
The E. R. Sears Scholarship Fund in Genetics
Contents
List of Participants at the 9th Symposium
James W. Allen, Charles F. Shuler, and Samuel A. Latt: EXTENSION OF BrdU-DYE ANALYSIS OF DNA REPLICATION AND SISTER CHROMATID EXCHANGE FORMATION TO IN VIVO SYSTEMS
G. Gavazzi: THE GENETIC COMPLEXITY OF THE R LOCUS IN MAIZE
James N. Thompson, Jr.: ANALYSIS OF GENE NUMBER AND DEVELOPMENT IN POLYGENIC SYSTEMS
Hirofumi Uchimiya, Kevin Chen and S. G. Wildman: POLYPEPTIDE COMPOSITION OF FRACTION I PROTEIN AS AN AID IN THE STUDY OF PLANT EVOLUTION
Donald L. Riddle: A GENETIC PATHWAY FOR DAUER LARVA FORMATION IN CAENORHABDITIS ELEGANS
Moshe Feldman: HISTORICAL ASPECTS AND SIGNIFICANCE OF THE DISCOVERY OF WILD WHEATS
Winston J. Brill: GENETICS OF NITROGEN FIXATION
Ruth Kavenoff and Brian C. Bowen: ON THE ORGANIZATION OF DNA IN ISOLATED BACTERIAL CHROMOSOMES
J. R. S. Fincham: A GENE-ENZYME RELATIONSHIP IN NEUROSPORA
Gary Stein, Janet Stein, Lewis Kleinsmith, William Park, Judith Thomson, Robert Jansing, Elizabeth Shephard, and Siegfried Detke: CHROMATIN AS A MODEL SYSTEM FOR STUDYING THE REGULATION OF HISTONE GENE EXPRESSION IN MAMMALIAN CELLS
Cumulative Contents of the Proceedings of the Stadler Genetics Symposia

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Stadler Genetics Symposia, volume 09, 1977 : Preliminaries and back matter
(University of Missouri, Agricultural Experiment Station, 1977) Stadler Genetics Symposium (9th : 1977 : Columbia, Missouri)
Polypeptide composition of fraction I protein as an aid in the study of plant evolution : (chloroplast DNA, age of genera and species, origin of genomes, composition of proteins as affected by amphiploidy)
(University of Missouri, Agricultural Experiment Station, 1977) Uchimiya, Hirofumi; Chen, Kevin; Wildman, S. G.; Stadler Genetics Symposium (9th : 1977 : Columbia, Missouri)
Fraction 1 protein (F-1-P), found in all green plants, consists of eight large subunits (LS) coded by chloroplast DNA and eight small subunits (SS) coded by nuclear DNA. By electrofocusing in 8M urea many different species of F-1-P from all parts of the Plant Kingdom, the LS is invariably found to resolve into three polypeptides of different isoelectric points and the SS into from one to four polypeptides. During evolution of new plant species by amphiploidy the composition of the LS is always determined by the maternal parent, but both parents make equal contributions to the composition of the SS. In the case of N. tomentosiformis (n=12; 1SS) [male sign] x N. sylvestris (n=12; 1SS) [female sign] [rightwards arrow] N. tabacum (n=24; 2SS) [male sign] x N. glutinosa (n=12; 2SS) [female sign] [rightwards arrow] N. digluta (n=36; 4SS) a F-1-P evolved containing 4SS polypeptides. None of these arose by point mutation during speciation, although the SS of F-1-P of N, digluta could have eight differences in amino acid sequence compared to N. sylvestris or N. tomentosiformis, the differences being the consequence of amphiploidy. Using this example, together with F-1-P composition in parasexual hybrids, it is hypothesized that the genetic information for more than one SS polypeptide is non-allelic and most likely located on heterologous chromosomes. The study of F-1-P in 62 species of Nicotiana provides a model system whereby the LS is an indicator of the evolutionary age of one genus relative to another and the SS an indicator of the age of one species relative to another. The SS can also serve to designate a new species of plant, while the LS has been used to trace the origin of genomes in amphiploids.
Analysis of gene number and development in polygenic systems : (polygenes, variation, selection, pattern)
(University of Missouri, Agricultural Experiment Station, 1977) Thompson, James N.; Stadler Genetics Symposium (9th : 1977 : Columbia, Missouri)
The assumption that quantitative variation is produced by a large number of genes is re-examined. In fact, one finds that often only a small number of loci are involved. This, therefore, opens to careful study the developmental effects associated with polygenic variation.
Chromatin as a model system for studying the regulation of histone gene expression in mammalian cells : (mRNA, chromosomal proteins, transcription, cell cycle)
(University of Missouri, Agricultural Experiment Station, 1977) Stein, Gary; Stein Janet; Kleinsmith, Lewis; Park, William; Thomson, Judith; Jansing, Robert; Shephard, Elisabeth; Detke, Siefried; Stadler Genetics Symposium (9th : 1977 : Columbia, Missouri)
Histone gene expression was studied during the cell cycle of continuously dividing HeLa S3 cells and after stimulation of confluent monolayers of WI-38 human diploid fibroblasts to proliferate. The presence of histone mRNA sequences was assayed by hybridization to a 3H-tabeted, single-stranded DNA complementary to histone mRNA molecules. In HeLa S3 cells histone mRNA sequences were found in the nucleus and associated with polyribosomes during S phase but not during G1 phase. Transcripts of S phase chromatin contained histone mRNA sequences, but those of G1 phase chromatin did not. Similarly, in WI-38 cells association of histone mRNA sequences with polyribosomes and transcription of histone mRNA sequences from chromatin parallel DNA replication. Taken together, these results suggest that the regulation of histone gene expression resides, at least in part, at the transcriptional level. However, other results suggest that the coupling of histone gene expression and DNA synthesis is mediated post-transcriptionally. Chromatin reconstitution studies provide evidence that (i) a component of the complex and heterogeneous non histone chromosomal proteins plays a key role in activation or derepression of histone gene transcription during the period of the cell cycle when DNA is replicated, (ii) the chromosomal proteins and/or the DNA sequences involved in the regulation of histone gene expression may be similar in mouse and human and (iii) phosphate groups associated with the S phase non histone chromosomal proteins appear to be functionally involved in the control of histone gene readout.
A genetic pathway for dauer larva formation in caenorhabditis elegans : (nematode, development, neuron)
(University of Missouri, Agricultural Experiment Station, 1977) Riddle, Donald L.; Stadler Genetics Symposium (9th : 1977 : Columbia, Missouri)
C. elegans is a roundworm, a free-living soil nematode. The dauer larva is a non-feeding, non-growing larval stage which is formed under conditions of starvation. It possesses a relatively impermeable cuticle and differs from all other larval stages in behavior and morphology. Dauer larva formation is a "developmental switch" in the life cycle which offers special advantages for genetic study. A partial genetic pathway for dauer larva formation has been established. Genetic characterization of additional mutants should reveal more details of this pathway. One class of mutants already characterized exhibits morphological alterations in sensory neurons, as determined by electron microscopy. Such mutants are useful for the study of nerve morphogenesis.

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