In this week's Nature Genetics, a group led by scientists from the University of Sydney reports sequencing the genome of the koala, the only extant species of the marsupial family Phascolarctidae. The researchers found an expansion within a cytochrome gene family involved in detoxification that allows koalas to live off of phenolic-rich eucalyptus leaves, and describe smell and taste receptor genes that help koalas choose which leaves to eat. They also characterize novel lactation proteins that protect young in the pouch and annotated immune genes important for response to chlamydial disease. "The genome provides a springboard for conservation of this biologically unique and iconic Australian species," the authors conclude. GenomeWeb has more on this study, here.
And in Nature Plants, an international research team presents a genomic analysis of two fern species — Azolla filiculoides and Salvinia cucullata — uncovering new details about the genetics of this seed plant sister group. They present evidence for episodic whole-genome duplication in ferns: one occurring in Azolla following its divergence from Salvinia, and an earlier one predating the origin of core leptosporangiate ferns. Among the investigators' other findings is a fern-specific gene that confers insert resistance and appears to be derived from bacteria via horizontal gene transfer. Overall, the work provides new insights into the poorly understood genomics of ferns and will help address fundamental questions in the evolution of plant life, the researchers write. The Scan also covers this, here.
Meanwhile, in Nature Communications, a trio of researchers from the University of Cambridge publishes a genome-wide association study of loneliness and sociability using data on 487,647 participants of the UK Biobank who provided questionnaire responses about their perceived loneliness, the frequency of interactions with others, and the quality of these interactions. The researchers find 15 genomic loci for loneliness and demonstrate a likely causal association between obesity and increased susceptibility to loneliness and depressive symptoms. They also pinpoint loci linked to regular attendance at a sports club or gym, pub or social club, or religious group. "Further study of these traits may identify novel modifiable risk factors associated with social withdrawal and isolation," the researchers say. And there’s more on this study at GenomeWeb, here.