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The meiotic behavior of two graded series of deletion mutations in the ADE8 gene in Saccharomyces cerevisiae was analyzed to investigate the molecular basis of meiotic recombination. Postmeiotic segregation (PMS) was observed for a subset of the deletion heterozygosities, including deletions of 38 to 93 base pairs. There was no clear relationship between deletion length and PMS frequency. A common sequence characterized the novel joint region in the alleles which displayed PMS. This sequence is related to repeated sequences recently identified in association with recombination hotspots in the human and mouse genomes. We propose that these particular deletion heterozygosities escape heteroduplex DNA repair because of fortuitous homology to a binding site for a protein.

This update adds thirty-four doctoral dissertations and one master's thesis utilizing oral evidence to the ones listed last year in "Oral History Dissertations, 1980-1982, and Masters Theses, 1977-1982," the first annual updating of "Oral History Dissertations, 1977-1981," which appeared in the Oral History Review in 1982. Most of these additional works came to the compiler's attention through the July 1983 to June 1984 issue of Dissertation Abstracts International and Masters Abstracts. The following entries are organized alphabetically by degree level and year of completion. Except for a few cases, inclusion in the list is based upon specific mention in the abstract that the author used either "oral history," "oral interviews," "personal

A methodology is presented for determining the minimum energy condition for a spark ignition engine for given inlet conditions and ignition system. This is accomplished with a new misfire detection technique which yields good repeatability. The effects of changes in the equivalence ratio, turbulence level, and residual gas fraction are investigated. A simplified thermal ignition model is evaluated at the experimentally determined ignition limits. The model is unable to satisfactorily predict the effect of engine speed changes. The results suggest that the use of a fully developed value for the eddy diffusivity during the ignition process is invalid in spark ignition engines.