In Nature this week, a team of Finnish and Norwegian researchers report on a genetic strategy to determine maturity in Atlantic salmon, offering insights that may impact population management in the fish. While it is known that adult male and female Atlantic salmon differ in size and have differing rates of maturity, the genetic underpinnings of these differences was unclear. The team examined the genomes of salmon from 57 wild populations and identified variants of a gene that operates differently in males and females. They found that with the gene, the dominant allele in one sex is recessive in the other — a phenomenon known as sex-dependent dominance. Because this same gene has been implicated in human puberty, the researchers speculate that the genetic basis of maturation may be conserved across species. GenomeWeb has more on this study here.
And in Nature Genetics, a group led by Stanford University researchers publishes the discovery of a gene that incorporates sugars into corn and rice grains, and which may be responsible for the differences in seed sizes between wild and domesticated grains. Early farmers typically selected large seeds in grain crops for their higher nutritional value, resulting in the larger size of domestic strains. To determine what causes size variation, the investigators compared the genetic sequences of cultivated corn and its wild ancestor. From this, they identified a mutation in a gene that had been selected for during the domestication process and that gene transports hexose sugars such as glucose across a specific cell barrier. A closely related gene was found to be a selection target in rice. The researchers suggest that the finding might help in the creation of new high-yield corn and rice varieties.