In Nature this week, a group of Chinese investigators publish the genomic sequences of 446 geographically diverse versions of the wild rice species Oryza rufipogon, the immediate ancestral progenitor of cultivated rice, and from more than 1,000 varieties of cultivated rice to create a comprehensive map of rice genome variation. The findings reveal that rice was originally domesticated from a small population of wild rice in southern China and was later crossed with wild rices in other areas of Asia. The study "provides an important resource for rice breeding and an effective genomics approach for crop domestication research."
Meanwhile, in Nature Genetics, Columbia University researchers describe a large-scale sequencing effort to identify the genetic components of schizophrenia risk. They sequenced the exomes of 231 people with the disease as well as their unaffected parents and found that people with schizophrenia have a greater than expected number of new mutations that trigger amino acid alterations in protein sequences. Four genes in particular were identified as harboring the alterations among all schizophrenia patients examined. The findings suggest that new mutations contribute to disease risk, but that there is also substantial contribution by mutations in genes with higher expression in early fetal life.