Nearly every culture has taboos on incest.
https://en.wikipedia.org/wiki/Incest comments "sexual relations with a first-degree relative (such as a parent or sibling) are almost universally forbidden".
If you were Christian you would point to Leviticus 18:6-18 for the Biblical definition of incest. https://www.biblegateway.com/passage/?search=Leviticus+18%3A... .
As the Wikipedia page I linked to further states: "cultural anthropologists have noted that inbreeding avoidance cannot form the sole basis for the incest taboo because the boundaries of the incest prohibition vary widely between cultures, and not necessarily in ways that maximize the avoidance of inbreeding."
The further refinement of your question might be, how do the unique aspects of the astrological tradition affect inbreeding?
In order to test your hypothesis you would need to define gotras. I will quote from the Wikipedia page you linked to:
> the definition of gotra as descending from eight sages and then branching out to several families was thrown out by the Bombay High Court. The court called the idea of Brahmin families descending from an unbroken line of common ancestors as indicated by the names of their respective gotras "impossible to accept." The court consulted relevant Hindu texts and stressed the need for Hindu society and law to keep up with the times, emphasising that notions of good social behaviour and the general ideology of the Hindu society had changed. The court also said that the mass of material in the Hindu texts is so vast and so full of contradictions that it is a near-impossible task to reduce it to order and coherence.