In PLoS Genetics this week, DeCode Genetic’s Kari Stefansson and his colleagues report on both the cis and trans components of heritability within and across samples from 722 Icelandic family cohorts, which they characterized "using identity-by-descent estimates from long-range phased genome-wide SNP data and gene expression measurements for [about] 19,000 genes in blood and adipose tissue." The researchers at DeCode and their academic colleagues found that heritability at cis loci contributed largely to correlations they observed in gene expression measurements across samples. "We obtained similar estimates of the cis components of heritability using [identity-by-descent] between unrelated individuals, indicating that trans-generational epigenetic inheritance does not contribute substantially to the 'missing heritability' of gene expression in these tissue types," Stefansson et al. write.
Also in PLoS Genetics, a team led by investigators at the University of Montreal describes "a population genetic approach to mapping neurological disorder genes using deep re-sequencing" of functional regions. The team re-sequenced candidate genes association with autism and schizophrenia in 285 patients and found that "MAP1A, GRIN2B, and CACNA1F were consistently identified by different methods as having significant excess of rare missense mutations in either one or both disease cohorts." Overall, the team says its study shows that "genes associated with complex disorders can be mapped using re-sequencing and analytical methods with sample sizes far smaller than those required by genome-wide association studies."
A trio of researchers at Australia's University of Queensland and the Rensselaer Polytechnic Institute in New York present an approach for the "quantitative prediction of miRNA-mRNA [interactions] based on equilibrium concentrations" in this week's PLoS Computational Biology. The researchers say that while their method does not indicate whether a given "targeted mRNA is degraded and/or its translation to protein inhibited," it does predict "target sites on mRNA that minimize the calculated free energy of duplex formation, compute the free energy change involved in unfolding these sites, and use these energies to estimate the extent of duplex formation at specified initial concentrations."
And in this week's PLoS Biology, researchers in Germany and the US show that the axon guidance receptor Neuropilin-1, or Npn-1, "contributes to axon-axon interactions that differentially control sensory and motor innervation of the limb" which they found via cell-type specific ablation of the reception in spinal motoneruons and sensory neurons and in the dorsal root ganglia. "Removal of Npn-1 from sensory neurons results in defasciculation of sensory axons and, surprisingly, also of motor axons," the authors write.