The genome sequence of the common carp, Cyprinus carpio, is reported in a paper published online this week in Nature Genetics. The results can help to uncover the genetic basis of differences in wild and farmed carp varieties.
Carp is the top species of farmed fish; the common carp is responsible for up to 10% of worldwide freshwater aquaculture production, or more than three million metric tons of fish, per year. In addition, some varieties, such as koi, are also used for decorative purposes in outdoor landscaping and tanks. Carp varieties differ widely in traits such as skin color, scale pattern and body size.
Xiaowen Sun and colleagues sequenced the genomes of 33 fish from four wild populations and six domestic strains. Between two common varieties, Hebao and Songpu, they found 894 genes that are expressed at different levels. Many of these genes are involved in scale development and pigmentation. For example, the gene slc7a11 converts brown pigment to yellow and red. The genome sequence may also provide information on economically important traits and help breeders to make genetic improvements to farmed carp.