with no apparent gene history..
the kid wouldn't be old enough to even imagine if not do, some karma responsible for this state.
so, we have 2 options:
1) blame it on the ancestors karma
2) or on the karma of past lives.
we have seen child prodigies, expressing art/talent right from the tender age of 3 or 4 years.
even when the family tree doesn't have a single person with a similar taste.
even when the child was not exposed to circumstances congenial for the conscious or sub-conscious absorption of these tastes.
so, there is past janma carry over!
we consider mainly 2 houses, to judge the past lives.
1) 5th house
2) 12th house.
as per the bhavat bhava chinthanam, the 5th of 5th, ie the 9th too should be considered, just like 12th of 12th, ie the 11th.
but how many past lives can we judge from all these?
it needs atleast a thousand years of study to get to start appreciating astrological studies!