https://www.frontiersin.org/articles/10.3389/fimmu.2017.00209/full
Immunologisen puolustuskyvyn kehittyminen on kaiken elollisen olemassaolon perustavia piirteiä.
- Scottish Fish Immunology Research Centre, University of Aberdeen, Aberdeen, UK
The earliest jawed vertebrates (Gnathostomes) would likely have had
interferon (IFN) genes, since they are present in extant cartilaginous
fish (sharks and rays) and bony fish (lobe-finned and ray-finned fish,
the latter consisting of the chondrostei, holostei, and teleostei), as
well as in tetrapods. They are thought to have evolved from a
class II
helical cytokine ancestor, along with the
interleukin (IL)-10 cytokine
family. The two rounds of whole genome duplication (WGD) that occurred
between
invertebrates and
vertebrates (
1)
may have given rise to additional loci, initially containing an
IL-10
ancestor and
IFN ancestor, which have duplicated further to give rise to
th
e two loci containing the IL-10 family genes, and potentially the
IFN
type I and
IFN type III loci (
2).
The timing of the divergence of the
IFN type II gene from the IL-10
family genes is not clear but was also an
early event in vertebrate
evolution. Further WGD events at the base of the teleost fish, and in
particular teleost lineages (cyprinids, salmonids), have duplicated the
loci further, giving rise to
additional IFN genes, with tandem gene
duplication within a locus a common occurrence. Finally,
retrotransposition events have occurred in different vertebrate lineages
giving rise to
further IFN loci, with large expansions of genes at
these loci in some cases. This review will initially explore the likely
IFN system present in the earliest Gnathostomes by comparison of the
known cartilaginous fish genes with those present in mammals and will
then explore the changes that have occurred in gene
number/diversification, gene organization, and the encoded proteins
during vertebrate evolution.
Chris J. Secombes* and 
Jun Zou
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