WIKIMEDIA, BERT DE TILLY
Species: Mallard duck, Anas platyrhynchos
Genome size: ~ 13 billion bases pairs
The duck is a known natural host of nearly all influenza A
WIKIMEDIA, BERT DE TILLY
Species: Mallard duck, Anas platyrhynchos
Genome size: ~ 13 billion bases pairs
The duck is a known natural host of nearly all influenza A virus subtypes (including H5N1). Researchers have now sequenced the whole genome of a female duck from Beijing. Comparisons of the duck’s sequence to those of other birds and mammals indicates that, like chickens and zebrafinches, the duck harbors nearly half as many immune-related genes as do mammals.
Researchers also performed deep transcriptome analysis to identify genes that are responsive to bird flu viruses. For the most part, the duck does not show symptoms following infection with the influenza virus. The research team found a highly diverse set of beta-defensin genes in the duck, which may explain the waterfowl’s viral defense mechanisms. By comparing gene expression in the lungs of ducks infected with a highly pathogenic...
Y. Huang et al., “The duck genome and transcriptome provide insight into an avian influenza virus reservoir species,” Nature Genetics, doi: 10.1038/ng.2657, 2013.
Species: Floating bladderwort, Utricularia gibba
Genome size: 80 million base pairs
The floating bladderwort (Utricularia gibba) is a carnivorous plant with a highly specialized hunting technique. The plant pumps water into tiny chambers, or bladders, creating a vacuum in each one that can suck in and trap unsuspecting insect prey. Despite this complex behavior, the bladderwort’s recently sequenced genome indicates that the aquatic plant has the smallest genome–80 million base pairs–of any higher plant that has been sequenced so far. By comparison, plants like the grape and the tomato have 490 and 780 million base pairs respectively. Yet the bladderwort has roughly the same number of genes as the grape and tomato. The reason for this discrepancy lies in the bladderwort’s systematic shedding of so-called “non-coding DNA”, or DNA that does not code for proteins.
The vast majority of human DNA, about 98 percent, is non-coding, or what used to be called “junk” DNA. In fact, complex organisms have a preponderance of non-coding DNA. However, the bladderwort genome is comprised of only 3 percent non-coding DNA, despite three separate incidents of genome doubling, where offspring receive two full copies of the entire genome, in its evolutionary history. The finding contradicts recent high profile projects, such as ENCOD