In this week's Nature Plants, a team led by scientists from the Chinese Academy of Sciences publishes a near-complete genome assembly of the snapdragon, Antirrhinum majus L, a member of the Plantaginaceae family and important model for molecular and developmental genetics. The assembly comprises 510 megabases of genomic sequence and contains 37,714 annotated protein-coding genes. Comparative and evolutionary analyses reveal a whole-genome duplication event about 46 million to 49 million years ago, and the investigators discovered the genetic architectures associated with complex traits such as flower asymmetry and self-incompatibility. "The genome sequence obtained in this study not only provides a representative genome sequenced from the Plantaginaceae but also brings the popular plant model system of Antirrhinum into the genomic age," the authors write.
And in Nature Neuroscience, an international research team reports a genome-wide association study implicating the dysregulation of fetal neurodevelopment-related genes in the risk for various psychiatric disorders later in life. The researchers used the Integrative Psychiatric Research Consortium study — one of the largest single-population samples of genotyped psychiatric patients in the world — to identify four novel genome-wide significant loci encompassing variants predicted to regulate genes expressed in certain areas of the developing brain during mid-gestation in addition to confirming previous reports of SNP heritability for major psychiatric disorders. "This epoch," they write, "is supported by partitioning cross-disorder single-nucleotide polymorphism heritability, which is enriched at regulatory chromatin active during fetal neurodevelopment."
And in Nature Communications, collaborators from the US, Australia, and Europe present a large-scale genome-wide association study of circadian rhythms that suggests genetics may influence whether someone is a "morning person." Using data from 697,828 individuals participating in the UK Biobank and 23andMe, the researchers find 327 new genetic loci that may be associated with chronotype. Since participants' morningness is based on self-reporting, the investigators also examined data from around 85,000 participants for whom objective measures of sleep were available via activity monitors, finding that the chronotype loci are associated with sleep timing, although not quality or duration. They also find that being a morning person is causally associated with better mental health, but does not affect body mass index or risk of type 2 diabetes. GenomeWeb has more on this, here.