The genome sequence of the duck is reported this week in Nature Genetics. This work identifies potential genetic factors influencing the duck's response to avian influenza infection, and will facilitate further studies to understand the mechanism for the greater protection seen in this type of waterfowl.
The recent emergence of avian influenza subtype H5N1 has contributed to widespread influenza outbreaks in poultry, and the duck has been implicated as a reservoir species by which the virus has spread. The duck, a natural host of influenza A viruses (including H5N1), is known to often remain asymptomatic following influenza infection.
Ning Li and colleagues sequenced the whole genome of a female duck from Beijing. Comparisons to the genome sequences of other birds and mammals showed that the duck contains fewer immune-related genes than mammals, similar to observations in the chicken and zebra finch genomes. By comparing gene expression in the lungs of ducks infected with either highly or weakly pathogenic avian influenza H5N1 viruses, the authors identify genes whose expression patterns are altered in response to avian influenza viruses. They also identify factors that may be involved in duck host immune response to avian virus infection, including the avian and mammalian beta-defensin gene families.