Sore, at this point in our knowledge it’s very reasonable to work on the assumption that new races contributed the new genes.
But we may discover they’re just beneficial changes by radiation.
Intriguing that the Laschamp Event (75% weakening of the magnetosphere) happened 41,400 (±2,000) years ago: roughly approximating the time of the ‘new’ races in SE Asia.
just something to bear in mind!
What I really want found is evidence of the “giants” mentioned in practically all myths- not ‘Hobbits’!
The Laschamp Event evidence shows that the magnetic field of the Earth can change quickly, and just as quickly change back. Other magnetic field evidence shows large increases and polarity changes. Either the magnetic field of the Earth has an unknown mechanism as its cause (not unlikely, since it remains unexplained), or the Earth is sometimes in the presence of an outside magnetic field (perhaps from some kind of massive solar event). Either way, magnetic field fluctuations are just a uniformitarian alibi for events — such as global glaciation — that are caused by brief, unusual events. The Earth’s magnetic field means squat to the Earth’s climate.
[snip] What is remarkable is the speed of the reversal: “The field geometry of reversed polarity, with field lines pointing into the opposite direction when compared to today’s configuration, lasted for only about 440 years, and it was associated with a field strength that was only one quarter of today’s field,” explains Norbert Nowaczyk. “The actual polarity changes lasted only 250 years...” [/snip]
https://www.sciencedaily.com/releases/2012/10/121016084936.htm