DNA-busting radiation from star-killing supernova could have influenced evolution on Earth

[Admin]

A distant star-killing supernova could have bombarded Earth with radiation strong enough to shift the course of evolution.

DNA-busting radiation from star-killing supernova could have influenced evolution on Earth : Read more

 

[bwana4swahili]

About the right time for hominin specification as well... Maybe it wasn't like the movie '2001: A Space Odyssey' after all!?

 

[Unclear Engineer]

And about the time that the most recent "ice age" sequence started, too.

But correlation does not prove causation.

One thing that seems odd is that fish in water should have more radiation shielding than species living on land.

 

[bwana4swahili]

And about the time that the most recent "ice age" sequence started, too.

But correlation does not prove causation.

One thing that seems odd is that fish in water should have more radiation shielding than species living on land.

But a much better track record of their divergent species than land animals.

 

[Unclear Engineer]

But a much better track record of their divergent species than land animals.

The trouble with the statistical "correlation" is that the people who already had an event time for a supernova went looking for any biological changes documented by any study. And, all they apparently found was one study of one genus of fish in one lake in Africa.

So, what are the odds of something happening somewhere at about the same time that they are searching for? Several things happened, including the beginning of the next glaciation type climate change, the rise of the Central American isthmus out of the ocean surface, and probably a lot of other things, too. But, they could not blame the other things on the supernova.

It requires a world-wide indication of an accelerated mutation rate at that time to really have any statistical significance. The finding for a single genus of fishes in one lake seems merely coincidental.

 

[Torbjorn Larsson]

So, who's ready for a cosmic fishing trip?

Apparently the paper was.

The association is spurious. From one paper that address viral radiation and clearly ties it to the diversification of the host, they talk about double stranded DNA breaks. But the viral paper found 13 RNA and 4 DNA virus groups - where RNA viruses has no problem to mutate rapidly - and the only group that they checked for acceleration was an RNA virus. The larger problem is that it clearly states that this was for the entire last 2-3 Myrs and was likely due to local host radiation.

The reference paper does not seem to claim "three pulses" of the viral paper and I don't want to dig further into its references, but it says this:

Additionally, many Tanganyikan cichlid species show complex distribution patterns, presumably shaped by the patchy distribution of
habitats along the lake’s shoreline in combination with major lake
level fluctuations (among other reasons) (see e.g. Sturmbauer et al.,
2001). During periods of the most extreme low water stands, the
lake was subdivided into three sub-basins (Salzburger et al.,
2014). This previous separation of the lake in sub-basins is
reflected today by many sister-species pairs showing a north versus south distribution (probably reflecting allopatric diversification
in the sub-basins) or an east versus west distribution (probably
reflecting dispersal along the paleo shore lines).

 

[Torbjorn Larsson]

About the right time for hominin specification as well...

Nothing is "specified" (specification) in evolution, but there is speciation (species divergencies). Hominins (Panina, Homonina) started to speciate 6 million years ago.

We don't know much about chimp evolution, but chimps and bonobos split later at 2 million years ago.

On the Hominina side, Homo Erectus split between 2.5 and 2 million years ago. But seeing how it is spurious timing, it doesn't say much. The real interesting genetic reorganization is the human chromosome 2 fusion, which is possibly 1 million years ago when the human tree of archaics and moderns started to diverge and reconverge. That wasn't radiation mediated AFAIK, chromosome rearrangements are spurious.