Twelve years after they started dating, they married. The family disapproved. Surender’s grandmother and Preeti’s mother were from the same “gotra,” or clan. Hindu clans prohibit marriage within the descendants of an unbroken male line.
The Wiki page on "gotra" suggests they "only" have to go back seven generations (I don't know any of my ancestors beyond five generations and the father of one of my great-grandfathers was never known; would that be scandalous in India?), which seems to imply extreme complication. If each female ancestor has her own unique gotra, in seven generations there would be 64 gotras. Unless there are thousands of gotras, it must be very common for a prospective bride and groom to overlap. Little wonder that arranged marriages are common.
In practice, there really are several dozen gotras (at least among the Brahmins), if not hundreds.
The traditional practice was for Brahmins to declare their exact line of descent alongside the gotra, by naming five noteworthy ancestors (pravara rishis), starting from the top level saptarishi ancestor gotra(one of seven). Some of the saptarishis famously didn't get along, and their descendants are considered incompatible matches for marriage. When considering a marriage alliance from a family with the same top level saptarishi gotra, it was considered acceptable if at least three of the five pravara rishis were different, ie, a distant branch of the family. As families lost their traditions, people identified their nodal pravara rishi as the gotra, which is how most people today know them. In addition, in ancient times the custom was for non-brahmins to state the gotra & lineage of their family priest when performing religious rituals, and ended up adopting them.
I suppose this was an ancient way to ensure genetic diversity and prevent pregnancy losses. There is already quite a bit of evidence that consanguinity leads to miscarriages [0].
Funnily enough, the strict endogamy among Indian caste groups actually leads to far less diversity. There have been many genetic studies on this from Dr. Lal's and Dr. Thangaraj's group at Center for Cellular and Molecular Biology.
This was true in the southern clans as well. The practice of lineage splitting is well documented. As for the concept of gotra incompatibility, its something your astrologer might bring up, and not something well known among the general public.
> Unless there are thousands of gotras, it must be very common for a prospective bride and groom to overlap.
The brahmin communities have a handful of gothras as I understand it (7 or 8, depending on who you ask).
The relationship matrix is resolved by only tracking a single side of the family tree and making first cousins who are able to marry each other without complication on this topic. So it doesn't directly fix the inbreeding within insular communities, though that was its intention.
My father-in-law spent quite some time investigating this, as my clan is matrilineal in ancestry (still very patriarchal, just brother-sister family unit instead of husband-wife) with a history of cross-marriages from patrilineal men for treaties/allies.
Completely pointless pedigree certificate, felt like I was being picked for breeding instead of an equal partnership.
A dive into this sort of discrimination almost left me wondering why something with political eugenics didn't come out of India. Fears which I still have for the 2040s seeing the CAA and NRC.
From what I recall, some temples / priests / elders keep a record of this within a community. And yeah, that is one of the reasons why marrying outside your community, with or without your parent's consent, is such a big deal in India (not just with the Hindus who subscribe to gotras but also among other communities, as the emphasis on arranged marriages are often on "shared values" between the families. It's harder to determine what values an "outsider" or their family has, as it becomes harder to use your social circles to investigate them. )
Gotra is limited to only certain number of paternal lineages. In South India I see only tracking of one paternal lineage (generally consisting of 2-3 r'shis).
The Wiki page on "gotra" suggests they "only" have to go back seven generations (I don't know any of my ancestors beyond five generations and the father of one of my great-grandfathers was never known; would that be scandalous in India?), which seems to imply extreme complication. If each female ancestor has her own unique gotra, in seven generations there would be 64 gotras. Unless there are thousands of gotras, it must be very common for a prospective bride and groom to overlap. Little wonder that arranged marriages are common.