Why should only Sons carry the Gotra of their father, why can’t daughters? How does the Gotra of a daughter change just because she marries a person belonging to a different Gotra? What is the necessity of maintaining only the man’s ancestry, why not maintain that of women too? This was the question that was puzzling me about this Gotra system till recently, until I found out the scientific reasoning behind the Gotra system by chance while studying a puzzle in modern Genetics for which the biologists are trying to find an answer!
The Hindu Gotra System – Male Lineage Identification
The Gotra is a system which associates a person with his most ancient or root ancestor in an unbroken male lineage. For instance if a person says that he belongs to the Bharadwaja Gotra then it means that he traces back his male ancestry to the ancient Rishi (Saint or Seer) Bharadwaja. So Gotra refers to the Root Person in a person’s male lineage.
The Gotra system is practiced amongst most Hindus. See here for a
List of Hindu Gotras practiced by different sections of the Hindu Society
Brahmins identify their male lineage by considering themselves to be the descendants of the 8 great Rishis ie Saptarshis (The Seven Sacred Saints) + Bharadwaja Rishi. So the list of root Brahmin Gotras is as follows
- Angirasa
- Atri
- Gautam
- Kashyapa
- Bhrigu
- Vasistha
- Kutsa
- Bharadwaja
These 8 Rishis are called Gotrakarin meaning roots of Gotras. All other Brahmin Gotras evolved from one of the above Gotras. What this means is that the descendants of these Rishis over time started their own Gotras. The total number of established Gotras today is 49. However each of them finally trace back to one of the root Gotrakarin Rishi.
The word Gotra is formed from the two Sanskrit words Gau (meaning Cow) and Trahi (meaning Shed).
Note that the English word Cow is a derived word of the Sanskrit word Gau with the same meaning Gau.
So Gotra means Cowshed, where in the context is that Gotra is like the Cowshed protecting a particular male lineage. Cows are extremely important sacred animals to Hindus and there were a large number of best breeds of Cows that ancient Hindus reared and worshipped, and hence the name Gotra referring to the system of maintaining individual male lineages seems more appropriate.
A Girl and a Boy belonging to the same Gotra cannot marry!
This is the most important and the only rule in the Gotra system is I may say so. Yes, a Bride and a Bridegroom belonging to the same Gotra are considered to be siblings and hence it is prohibited for them to marry even if they belong to distant families. The reason given was since they belonged to the same ancestor, it will be like a brother marrying a sister which is known to cause genetic disorders in their offspring.
As I can see now, probably the prevention of marriages within the same Gotra was the only reason for the Gotra system to be created.
But again I used to think, what a crap, how can a boy and a girl belonging to two different families who haven’t met for centuries be considered as siblings?
Only until I was able to correlate a puzzle in modern Genetics to the Gotra system.
And now to the Science behind the Gotra System, but before that let us just check out one more additional rule related to marriages in the Gotra System.
Pravaras and the Gotras
Pravara is a list of most excellent Rishis in a Gotra lineage. As we saw earlier, some of the descendants of the most ancient Gotras started their own Gotras, however they maintained a list of Pravaras while doing so and attached the list of their most excellent Ancestors with this derived Gotras.
For instance the Vatsa Gotra has Bhargava, Chyavana, Jamadagnya , Apnavana as their Pravaras. What this means is that Vatsa Gotra has in its lineage all these Gotras and traces back its root to Bhrigu Rishi in the list of Gotrakarins.
The idea behind this Pravara system is probably to ensure that the derived Gotras still maintain track of their root Gotras, and this in turn is used to ensure that Bride and Bridegroom from no two derived Gotras coming from the same root Gotra marry each other. Every Gotra which is a derived Gotra maintains a list of Pravaras attached to it.
This is because, the essence of the Gotra system is finally to prevent marriages within the same Gotra. Now consider two derived Gotras which came from the same Gotra, then it might happen that over time people might forget that both these Gotras came from the same root Gotra, and may allow marriages within these Gotras since their names are different! To prevent this, the derived Gotras maintained a list of Pravaras (which were the prominent junctions where the derived Gotras got created), and the additional rule in the Gotra system is that, even if the Bride and Bridegroom belong to different Gotras, they still cannot get married even if just one of their Gotra Pravara matches.
This makes sense as this prevents marriages between derived Gotras which belong to the same root Gotra. This reminds me of a similar logic in the modern Object Oriented Programming in Software Systems.
Derived Classes
Consider a Class B which is derived from Class A, and another Class C which is also derived from Class B. Now Consider another Class D which is derived from both Class B and Class C (multiple inheritance like in C++). If we look at the immediate ancestry of Class D, then it appears that Class B and Class Care the parents of Class D. But if you look at the ancestors of Class B and Class C, then they are the Children of Class A. Now if we replace the classes A, B and C with Gotras, then we can see that even if two Gotras B and C are different Gotras, if they share the same parent Gotra A (enlisted in the form of Pravaras), then they will become siblings, and hence the marriage between two different Gotras sharing the same Pravara is not allowed.
But again the question remained – what is the basis to prevent marriages within the same Gotras even after thousands of years later the roots separated? How can hundreds of generations later they can still be considered to be the children of same parents just because they belong to same Gotra (male lineage) or to different Gotras sharing the same Pravara (again the male lineage)?
Now to the Science behind the Gotra System, but before that let us refresh a bit of our knowledge about Genetics.
-Chromosomes and Genes
Humans have 23 pairs of Chromosomes and in each pair one Chromosome comes from the father and the other comes from the mother. So in all we have 46 Chromosomes in every cell, of which 23 come from the mother and 23 from the father.
Of these 23 pairs, there is one pair called the Sex Chromosomes which decide the gender of the person. During conception, if the resultant cell has XX sex chromosomes then the child will be a girl and if it is XY then the child will be a boy. X chromosome decides the female attributes of a person and Y Chromosome decides the male attributes of a person.
When the initial embryonic cell has XY chromosome, the female attributes get suppressed by the genes in the Y Chromosome and the embryo develops into a male child. Since only men have Y Chromosomes, son always gets his Y Chromosome from his father and the X Chromosome from his mother. On the other hand daughters always get their X Chromosomes, one each from both father and mother.
So the Y Chromosome is always preserved throughout a male lineage (Father – Son - Grandson etc) because a Son always gets it from his father, while the X Chromosome is not preserved in the female lineage (Mother, Daughter, Grand Daughter etc) because it comes from both father and mother.
A mother will pass either her mother’s X Chromosome to her Children or her father’s X Chromosome to her children or a combination of both because of both her X Chromosomes getting mixed (called as Crossover). On the other hand, a Son always gets his father’s Y Chromosome and that too almost intact without any changes because there is no corresponding another Y chromosome in his cells to do any mixing as his combination is XY, while that of females is XX which hence allows for mixing as both are X Chromosomes.
-Y Chromosome and Vedic Gotra System
By now you might have got a clue about the relation between Y Chromosome and the Hindu Vedic Gotra System
Y Chromosome is the only Chromosome which gets passed down only between the men in a lineage. Women never get this Y Chromosome in their body. And hence Y Chromosome plays a crucial role in modern genetics in identifying the Genealogy ie male ancestry of a person. And the Gotra system was designed to track down the root Y Chromosome of a person quite easily. If a person belongs to Angirasa Gotra then it means that his Y Chromosome came all the way down over thousands of years of timespan from the Rishi Angirasa! And if a person belongs to a Gotra (say Bharadwaja) with Pravaras (Angirasa, Bhaarhaspatya, Bharadwaja), then it means that the person’s Y Chromosome came all the way down from Angirasa to Bhaarhaspatya to Bharadwaja to the person.
This also makes it clear why females are said to belong to the Gotra of their husbands after marriage. That is because women do not carry Y Chromosome, and their Sons will carry the Y Chromosome of the Father and hence the Gotra of a woman is said to be that of her husband after marriage. Pretty neat isn’t it?
All iz well so far, we now know the science behind the Gotra System. The ancient vedic Rishis hence very well knew the existence of the Y Chromosome and the paternal genetic material that was passed almost intact from father to Son, and hence created the Gotra system to identify their male lineages.Lord Buddha for instance belonged to Gautama Gotra which means that Buddha was a direct descendant of Rishi Gautama.
But then what is the reason to prevent marriages between individuals belonging to the same Gotra?
Before that lets let's understand a bit more about the Y Chromosome.
Weakness of Y Chromosome
The Y Chromosome is the only Chromosome which does not have a similar pair in the human body. The pair of the Y Chromosome in humans is X Chromosome which is significantly different from Y Chromosome. Even the size of the Y Chromosome is just about one third the size of the X Chromosome. In other words throughout evolution the size of the Y Chromosome has been decreasing and it has lost most of its genes and has been reduced to its current size. Scientists are debating whether Y Chromosome will be able to survive for more than a few million years into the future or whether it will gradually vanish, and if it does so whether it will cause males to become extinct! Obviously because Y Chromosome is the one which makes a person male or a man. And if it becomes extinct, Biologists are not sure whether any other Chromosome in our body will be able to completely take over its functionality or not.
And the reason for all this is that unlike other Chromosomes, there is no way for Y Chromosome to repair itself by doing cross over with its Chromosomal pair. All other Chromosomes come in similar pairs and when there the DNA of one Chromosome gets damaged the cell can repair it by copying over the DNA from the other Chromosome in that pair as both the Chromosomes in all other pairs are almost identical in nature. This copying (or crossing over as it is called) also allows different combinations of mix and matches to happen between the genes of mother and father and allows the best of the matches to survive and hence make the Chromosomes stronger as they evolve in successive generations. Even X Chromosomes in female undergo this mix and match since there are two X Chromosomes in women.
However Y Chromosomes do not have any corresponding equivalent Chromosome in its pair. It can exist only in a XY Combination and X cannot mix and match with Y except for a small 5% of X which matches with Y, while the remaining 95% of Y Chromosome which is crucial in the development of a male have absolutely no match at all!. It is this 95% of the Y Chromosome which is completely responsible in humans for creating a male or a man.
But at the same time, Y Chromosome has to depend on itself to repair any of its injuries and for that it has created duplicate copies of its genes within itself. However this does not stop DNA damages in Y Chromosome which escape its local repair process from being propagated into the offspring males. This causes Y Chromosomes to accumulate more and more defects over a prolonged period of evolution and scientists believe that this is what is causing the Y Chromosome to keep losing its weight continuously.
As discussed earlier other Chromosomes do not face this issue because they have corresponding pairs from both the parents and the DNA damage could be easily corrected most of the time by the mix and match process that takes place between the two Chromosomes in a pair. This Chromosomal crossover process eliminates damaged genes and is one of the key processes in evolution of life.
So to summarize, Y Chromosome which is crucial for the creation and evolution of males has a fundamental weakness which is denying it participation in the normal process of evolution via Chromosomal mix and match to create better versions in every successive generation, and this weakness MAY lead to the extinction of Y Chromosome altogether over the next few million years, and if that happens scientists are not sure whether that would cause males to become extinct or not. And that is because Scientists are not sure whether any other Chromosome in the 23 pairs will be able to take over the role of the Y Chromosome or not. Is there is an specific end date for Y Chromosome sometime in the future?
On the other hand, it is not necessary that humanity will not be able to survive if males become extinct. Note that females do not need the Y Chromosome, and since all females have X Chromosomes, it would be still possible to create a mechanism where X Chromosomes from different females are used to create offspring, say like injecting the nuclei from the egg of one female into the egg of another female to fertilize it and that would grow into a girl child. So yes, that would be a humanity where only females exist.
Now I understand why Hinduism and its Vedic core regard Mother Goddess or female divinity to be more powerful than all male divinity put together
Gotra System – Attempt to protect Y Chromosome from becoming extinct ?
The Vedic Rishis had observed the degeneration of the Y Chromosome and they wanted to maintain as many individual healthy unique Y Chromosome lineages as possible. That would give a fair chance for males to continue to exist because Y Chromosomes get passed on over generations with almost negligible change in their genetic combinations, as they do not take part in mix and match with other Chromosome.
So if the Rishis could devise a mechanism where in a given Y Chromosome had very little chance of adding more genetic defects in it, then they could probably succeed in either slowing down further degeneration of the Y Chromosome or even probably completely stop any further degeneration of the Y Chromosome.
And the only way to stop that was to ensure that the 5% of the Y Chromosome which can be mixed and crossed over with its X counterpart be protected so that the remaining 95% which does not take part in the mix and match process (which self heals by having duplicate copies of its genes) stays healthy.
Now we know even in modern Genetics that marriages between cousins will increase the risk of causing genetic disorders. That is because, say suppose there is a recessive dangerous gene in one person. What this means is that say a person is carrying a dangerous abnormality causing gene in one of his chromosome, but whose effect has been hidden in that person (or is not being expressed) because the corresponding gene in the pairing Chromosome is stronger and hence is preventing this abnormality causing gene from activating.
Now there are fair chances that his offsprings will be carriers of these genes throughout successive generations. As long as they keep marrying outside his genetic imprint, there is a fair chance that the defective gene will remain inactive since others outside this person’s lineage most probably do not have that defective gene. Now if after 5-10 generations down the line say one of his descendants marries some other descendant who may be really far away cousins. But then there is a possibility that both of them are still carrying the defective gene, and in that case their children will definitely have the defective gene express itself and cause the genetic abnormality in them as both the Chromosomes in the pair have the defective genes. Hence, the marriages between cousins always have a chance of causing an otherwise recessive, defective genes to express themselves resulting in children with genetic abnormalities.
So if the Vedic Rishis had allowed marriages within the same Gotras, then there were chances that the resulting male can be a victim of such defective gene expression, and any such gene expressions which took place in the 5% exposed area of the Y Chromosome would be fatal for the continuity of that Y Chromosome. Even after hundreds of generations there would still be chances of any defective genes being propagated within these successive generations, and marriage within the same Gotra would provide a golden opportunity for these genes to express themselves, there by causing the genetic abnormality in the offspring.
And hence the ancient Vedic Rishis created the Gotra system where they barred marriage between a boy and a girl belonging to the same Gotra no matter how deep the lineage tree was, in a bid to prevent inbreeding and completely eliminate all recessive defective genes from the human DNA.
Why only the selected list of Rishis as root Gotras? Why not somebody else?
When we look at the list of the Gotrakarni Rishis (ie the root Gotras), you may note that almost all of these Rishis are also Prajapatis – Prajapatis are those who were the immediate descendants of Brahma (the Creator God) – who then went on to create their own progeny or lineage.
So having the Gotra system start from the very beginning of human lineage looks more apt and logical as this is where the chromosomes and genes are still pure and free of any possible genetic defects. Hence the Prajapatis were selected as the root of the Gotra System.
Note that genetic defects or disorders or bad genes get eventually picked up over time during evolution due to genetic mutations.
