From single-SNP to wide-locus: genome-wide association studies identifying functionally related genes and intragenic regions in small sample studies.

Background: Genome-wide association studies (GWAS) have had limited success when applied to complex diseases. Analyzing SNPs individually requires several large studies to integrate the often divergent results. In the presence of epistasis, multivariate approaches based on the linear model (including stepwise logistic regression) often have low sensitivity and generate an abundance of artifacts.

Microbial populations associated with fixed- and floating-bed reactors during a two-stage anaerobic process.

Microbial populations associated with methanogenic fixed- or floating-bed bioreactors used for anaerobic digestion of lignocellulosic waste were investigated. Fluorescent in situ hybridization (FISH) was used to characterize microorganisms in samples obtained from different heights in the reactors, which were operated in a semi-continuous manner (feeding and mixing once every 2 days). The FISH results showed that Methanosaeta concilii cells were most numerous at the bottom of both reactors.