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This Week in PNAS: Sep 17, 2014

In the early online edition of the Proceedings of the National Academy of Sciences, Australian researchers outline results from their phylogenetic study of the beak and feather disease virus, a single-stranded DNA virus that infects parrots. Using quantitative real-time PCR and genome sequencing, the team looked at the prevalence and phylogenetic relationships, respectively, of the BFDV in various parrot species in Australia over eight years. The study's authors saw that the main host species and infection loads in a given area generally didn't correspond with the genetic variation detected in BFDV, though hybrid bird species and sub-species tended to have lower-than-usual viral loads when infected with BFDV.

The genetic structure of sorghum populations in Africa roughly coincides with the continent's ethnolinguistic patterns, according to another PNAS study. An international team led by Norwegian investigators genotyped hundreds of global sorghum accessions and seed lot representatives. In the process, the researchers detected three main sorghum populations in Central, Southern, and Northern Africa, which formed genetic clusters that tended to overlap with language families in these regions, the study's authors note, highlighting the inter-relationships between cultural groups, crop genetics, and traditional seed management methods. "We argue that efforts to strengthen African sorghum seed systems are more likely to be successful when building on, rather than seeking to replace, existing traditional seed systems and land races," they write.

Finally, a Czech Republic-led group considered the ecological and evolutionary effects of varying guanine and cytosine nucleotide levels in the genomes of monocot plants. In an effort to understand the distribution and consequences of this type of base composition, the researchers used flow cytometry to profile the GC-content in almost 240 plant species from 70 monocot families. The GC-content ranged from almost 34 percent to 49 percent in the monocot plants considered, the study's authors saw, and tended to vary with genome size and chromosome structure. Still, they note that the "discovery of several groups with very unusual GC contents highlights the need for in-depth analysis to uncover the full extent of genomic diversity."