The facts behind sagothra marriages

Hindus Gotra System: Scientific Meaning of Gotra in the Vedas

Since I am no expert in Genetics I want to ask if this is actually factual or just Pseudoscience".

This 's my reply: Sometime back one of my friend's parents rejected her marriage proposal to the person she loved just because he belonged to the same Gothra. But she went ahead and married him despite her parents' objection, which I think 's the right thing to do.

So when I supported my friend, need I  tell you again that the sagothra theory is Junk Science? Let me explain ...

According to the Brihadaranyaka Upanisad, Gautama and Bharadvāja, Viśvāmitra and Jamadagni, Vashishtha and Kaśhyapa and Shandilya were known as the seven sages (also known as saptarishi); Original Gothras came from them. The word gothra denotes the progeny of a sage (1). The word gothra means "lineage" in the Sanskrit language.(2)

To this list, Agastya is also sometimes added. These eight sages are called gotrakarins.

Gothra actually is equivalent to a clan. The original gothras that came from eight sages branched out to several families and castes forming several other gothras later. 

Gotra is always passed on from father to children among most Hindus. However, among the Malayali and Tulu people it is passed on from mother to child.

Some people in India consider sagothra (the compound word 'sagotra' is a union of the words 'sa' and 'gotra', where 'sa' means same or similar) marriages immoral, whereas  marriages between different gothras are encouraged by them.  The feeling of immorality pivots on an age-old belief that marriage should not take place between intra-clan (sagothra) .  This is because of the  belief  that since a couple belonging to the same gothra are the descendants of the same ancestral origin for several generations, they have the relation of brother and sister.

In India, the clan (gothra) has its origin not in the birth of people but derives from the gurus they followed. For example, families belonging to the Bharadwaja gothra are the followers of Bharadwaja Maharishi. But it does not necessarily mean that all its members belong to the same family. Different families in the same caste might have followed Bharadwaja Maharishi and acquired the name of Bharadwaja gothra.

Clans might have come into existence in a similar way too. In some castes, the clans were created by their profession and not by birth. For instance, the main clans in Viswakarmas (Viswabrahmins) trace their origin to their occupation. They have five main gothras — Saanaga, Sanatana, Ahabhoonasa, Patnarasa and Suparnasa. Saanaga denotes blacksmithy. Sanatana denotes carpentry, Ahabhoonasa metallurgical works, Patnarasa sculptures and Suparnasa goldsmithy. There are some other gothras among Viswakarmas. So the people of the same gothra in the above said clans do not necessarily belong to the same origin of birth or family. However, marriages among the same clan were banned.

Without assistance from science, we can trace the ancestry of families upto a few generations only. Beyond that it is not possible to go back. But how can the families having the same gothra say that they have descended from one source of family since time immemorial?

What is more interesting is we can see the name of the same gothra in different castes. For example, the Bharadwaja gothra can be found in both Brahmins and Viswakarmas. Marriages between Brahmins and Viswakarmas were banned not on the basis of gothra, but on the basis of caste. Moreover, marriages within the same caste are banned not on the basis of gothra, but on the basis of cult. For example, Brahmins have 18 cults. Inter-cult marriages among Brahmins are banned on the basis of their cult. The Reddy community has innumerable kinds and marriages between different kinds are banned.

There are sub-castes in several castes too. Like we have Naidu/ Kapu subcastes:  Naikkar, Telaga, Kamma, Toorupu kapu, Balija, Gawara, Ontario. Naidu's literal meaning is protector. Title of honour among Hindus in the Deccan. People usually  don't consider other sub-castes for marriages. 

It has become a practice to distort science in favour of traditional arguments, creating junk science in the process. Such is one about the genes in the clan. This pseudo-science practitioners say that as the genes descend from the same ancestor within a clan, marriages within the clan will trouble the offspring because of the conjugation of the same genes; that is why, the argument goes, our elders prohibited marriages within a clan. This theory is baseless because the people of a gothra descend from the families of different origin as we saw above. Moreover, the genes undergo change in course of time as the spouses come from different parents.

Ancient rishis or gurus or anybody else from that time didn't know anything about genetics to prohibit people from the same gothra marriage.   As people from one gothra  're marrying people from other gothras all these times, there would be enough exchange of genetic material between different gothras and we need not worry about sagothra  marriages now. 

A possible workaround for sagotra marriages is to perform a 'Dathu' (adoption) of the bride to a family of different gothra (usually dathu is given to the bride's maternal uncle who belongs to different gothra by the same rule) and let them perform the 'kanyadanam' ('kanya' (girl) + 'danam' (to give)). Such workarounds are used in some cases. So?

But according to this sagothra marriage theory,  permission for marriage between cross-cousins (children of brother and sister) 's given as they are of different gothras and in communities where gothra membership passed from father to children, marriages are allowed between a woman and her maternal uncle also.

 Gothra usually comes from the paternal side whereas genes mainly (Y chromosome and mitochondrial DNA being exceptions) come from both the paternal and maternal sides. So your cousins from father's side (father's sister's children) and cousins from mother's side (her brothers' children) might have different gothras from you but still are closely related to you genetically. So you cannot marry them even if they belong to different gothras, scientifically speaking (read here why: scientists' strong recommendation )

The fact that there are only eight sages and gothras based on them and this has been going on for a few thousand years, all of us have a healthy mix of all gothras and genes now. So, don't worry. You can marry sagothra people without any hesitation. 

References:

1. https://en.wikipedia.org/wiki/Gotra

2. https://familypedia.wikia.org/wiki/List_of_gotras