Amazing stuff!
"... Salmon hatch in rivers, where they spend a year or so before migrating to the sea – returning as adults to their riverbed of birth to spawn. This migration can extend over thousands of kilometres ...
The team discovered that magnetite within the salmon [nose] cells exists in compact, egg-shaped clusters. Each of these clusters measures around 200–300 nm in diameter, and contains roughly 100–200 individual crystals.
The team discovered that magnetite within the salmon [nose] cells exists in compact, egg-shaped clusters. Each of these clusters measures around 200–300 nm in diameter, and contains roughly 100–200 individual crystals.
The growth of crystals inside living cells is called biomineralization, which is used by magnetotactic bacteria to grow chains of magnetite crystals. The bacteria use these tiny “compass needles” to orient themselves with respect to Earth’s magnetic field, possibly to move to regions of optimal oxygen content.
Through subsequent genetic analysis, ... team discovered that the biomineralization genes expressed in salmon receptor cells were like those found in bacteria containing magnetite. This ... suggests that several billion years ago a magnetite-containing bacteria may have been incorporated into a more complex organism in a process called endosymbiosis – creating a distant ancestor of the salmon. ..."
Through subsequent genetic analysis, ... team discovered that the biomineralization genes expressed in salmon receptor cells were like those found in bacteria containing magnetite. This ... suggests that several billion years ago a magnetite-containing bacteria may have been incorporated into a more complex organism in a process called endosymbiosis – creating a distant ancestor of the salmon. ..."
From the abstract:
"Animals use geomagnetic fields for navigational cues, yet the sensory mechanism underlying magnetic perception remains poorly understood. ... Here, we discover that salmonid olfactory epithelium contains magnetite crystals arranged in compact clusters and determine that genes differentially expressed in magnetic olfactory cells, contrasted to nonmagnetic olfactory cells, share ancestry with an ancient prokaryote magnetite biomineralization system, consistent with exaptation for use in eukaryotic magnetoreception. We also show that 11 prokaryote biomineralization genes are universally present among a diverse set of eukaryote taxa and that nine of those genes are present within the Asgard clade of archaea Lokiarchaeota that affiliates with eukaryotes in phylogenomic analysis. ..."
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