The nonrecombining portion of the human Y chromosome has proven to be a valuable tool for the study of population history. The maintenance of extended haplotypes characteristic of particular geographic regions, despite extensive admixture, allows complex demographic events to be deconstructed. In this study we report the frequencies of 23 Y-chromosome biallelic polymorphism haplotypes in 1,935 men from 49 Eurasian populations, with a particular focus on Central Asia. These haplotypes reveal traces of historical migrations, and provide an insight into the earliest patterns of settlement of anatomically modern humans on the Eurasian continent. Central Asia is revealed to be an important reservoir of genetic diversity, and the source of at least three major waves of migration leading into Europe, the Americas, and India. The genetic results are interpreted in the context of Eurasian linguistic patterns.

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Certain yeasts cause large-scale spoilage of preserved food materials, partly as a result of their ability to grow in the presence of the preservatives allowed in food and beverage preservation. This study used robotic methods to screen the collection of Saccharomyces cerevisiae gene deletion mutants for both increased sensitivity and increased resistance to sorbic acid, one of the most widely-used weak organic acid preservatives. In this way it sought to identify the non-essential, non-redundant activities that influence this resistance, activities that might be the potential targets of new preservation strategies. 237 mutants were identified as incapable of growth at pH 4.5 in presence of 2 mM sorbic acid, while 34 mutants exhibit even higher sorbate resistance than the wild-type parental strain. A number of oxidative stress-sensitive mutants, also mitochondrial mutants, are sorbate-sensitive. This appears to reflect the importance of sustaining a reducing intracellular environment (high reduced glutathione levels and NADH/NAD and NADPH/NADP ratios). Sorbate resistance is also very severely compromised in mutants lacking an acidified vacuole, in vacuolar protein sorting (vps) mutants, in mutants defective in ergosterol biosynthesis (erg mutants) and with several defects in actin and microtubule organization. Sorbate resistance is, however, elevated with the loss of the Yap5 transcription factor; with single losses of two B-type cyclins (Clb3p, Clb5p); and with loss of a plasma membrane calcium channel activated by endoplasmic reticulum stress (Cch1p/Mid1p).

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