Most heritable traits, including many human diseases 1, are caused by multiple loci. Studies in both humans and model organisms, such as yeast, have failed to detect a large fraction of the loci that underlie such complex traits 2,3. A lack of statistical power to identify multiple loci with small effects is undoubtedly one of the primary reasons for this problem. We have developed a method in yeast that allows the use of dramatically larger sample sizes than previously possible and hence permits the detection of multiple loci with small effects. The method involves generating very large numbers of progeny from a cross between two strains and then phenotyping and genotyping pools of these offspring. We applied the method to 17 chemical resistance traits and mitochondrial function, and identified loci for each of these phenotypes. We show that the range of genetic complexity underlying these quantitative traits is highly variable, with some traits influenced by one major locus and others due to at least 20 loci. Our results provide an empirical demonstration of the genetic complexity of many traits and show that it is possible to identify many of the underlying factors using straightforward techniques. Our method should have broad applications in yeast and can be extended to other organisms.

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We conclude that loss of one copy of the eNOS gene, as observed in heterozygotic animals, has no effect on vascular reactivity, blood pressure or eNOS protein expression. Isoforms of NOS, other than eNOS are unlikely involved in blood pressure regulation but may participate in heart rate control.

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A series of cooking fire experiments were conducted to examine the effectiveness of residential kitchen fire suppression systems. A series of experiments provided data on the hazard associated with cooking oil fires. Then, a series of real-scale fire suppression experiments followed, using scenarios outlined in the UL 300A draft standard. Various fire suppression systems were tested. Experiments were conducted in a full-scale residential kitchen with dimensions 3.6 m x 3.4 m x 2.4 m high with an open doorway. Both gas and electric ranges were used. Several types of cooking pans were tested.The suppression systems tested included both automatic and manual suppression technologies. The manual devices included wet and dry chemical type extinguishers. The automatic systems included room-wide and range hood installed systems. The room wide systems included water mist and a residential sprinkler system. The hood installed systems included water mist and wet and dry chemical systems.Manual extinguishers consistently suppressed the oil fires while maintaining tenable conditions in the mock-up kitchen. One hood-installed wet chemical system tested demonstrated success in extinguishing the oil fires in all experiments, and maintained tenability in the mock up kitchen throughout most of the experiments. The hood-installed dry chemical system tested failed to extinguish the oil fire in all experiments, and introduced tenability hazards not present prior to the system activation. All other system types provided mixed results; they either could not reliably suppress the fire, or they consistently generated tenability hazards in the test kitchen.The effectiveness of ionization smoke alarms to provide early warning of fire were also tested as part of this study. The results showed that the smoke alarms inside, or just outside, the kitchen fire scenarios considered here generally activated several minutes before auto-ignition occurred, but not for all cases.The results of the experiments demonstrate the need to develop other approaches to kitchen fire safety such as ignition prevention technologies and reliable, early, and nuisance-free warning of pre-ignition conditions possibly through the development of specialized sensors or sensor combinations.