In this week's Nature, Svante Pääbo and his colleagues report on sequencing the genome of an archaic hominin to 1.9-fold coverage, using DNA obtained from a finger bone found in Denisova Cave in southern Siberia. The researchers compared that genome to those of Neandertals and modern humans. According to the researchers, the Denisova sample includes "some exceptionally archaic molecular (mtDNA) as well as morphological (dental) features" and that the population "is a sister group to Neanderthal." In addition, Pääbo et al. say that after the Denisova population split from Neandertals, they had separate population histories, and Denisovans, not Neandertals, contributed genes to present-day Melanesians. "In our view, these results show that on the Eurasian mainland there existed at least two forms of archaic hominins in the Upper Pleistocene: a western Eurasian form with morphological features that are commonly used to define them as Neanderthals, and an eastern form to which the Denisova individuals belong," the authors write.
A team led by Susan Celniker reports on the developmental transcriptome of Drosophila melanogaster. Using RNA-Seq, tiling microarrays, and cDNA sequencing, the researchers examined the transcriptome at 30 different developmental stages and found 111,195 new elements. "Our interrogation of the transcriptome of D. melanogaster throughout development has considerably expanded the number of building blocks used to make a fly," the researchers say. They add that "despite the depth of our sequencing, the annotation of the D. melanogaster transcriptome is not finished."
A team led by the National Institute on Alcohol Abuse and Alcoholism's David Goldman dove into finding alleles that influence impulsivity, which may contribute to psychiatric disorders and addiction. The researchers performed exon sequencing, looking at 14 genes related to serotonin and dopamine. They found a stop codon in HTR2B that is common in, and only found in, the Finnish population and that is associated with impulsivity. "This approach may be applicable to other complex behavioural traits, including those diseases for which impulsivity is itself an intermediate phenotype," the authors say.
A study in this week's Nature Genetics follows up on a previous genome-wide association study of narcolepsy-cataplexy. Researchers led by Emmanuel Mignot look at 10 loci previously associated with narcolepsy across three ethnic groups: African-Americans, Asians, and Europeans. From this, they homed in on a SNP in the 3' untranslated region of the P2RY11 gene, which encodes a purinergic receptor. The authors note that purinergic signaling is important in immune regulation. "These results identify P2RY11 as an important regulator of immune-cell survival, with possible implications in narcolepsy and other autoimmune diseases," the researchers write.