What is Gotra ?
The word Gotra comes from the Sanskrit Gau, cow and Trahi, a shed or stable. Translated literally, Gotra means ‘cowshed’ or ‘cow pen’ but the term has several connotations across Vedic literature. One of the earliest instances of ‘Gotra’ being used to denote paternal lineage appears around 1000 BCE in the Atharva Veda, a sacred Hindu text, where the word is used to refer to ‘clans’ or ‘groups’ descended from a common paternal ancestor. Subsequently, the Chandogaya Upanishad, another Hindu text written in the 7th century BCE, defines a Gotra as a mechanism through which the paternal lineage of an individual could be traced and identified while according to ancient Sanskrit linguist Panini, in his Astadhyayi, the term is equated with the word ‘progeny’.
Ancient Hindu scriptures such as the Upanishads and the Rigveda outline the conception and evolution of the Brahminical Gotric system. These texts posit that ‘Gotras’ emerged initially as a uniquely Brahminical concept; a marker of the paternal lineage of individuals within the caste.
Kashyap, Atri, Gautam Maharishi, Vashistha, Jamadagni and Bharadvaja are Seven Sages also known as "Sapta Rishi"; and the jambu maharishi (also known as renuka, belongs to sage Kashyap) the progeny of these eight sages are declared to be gotras.
Sapta Rishi: https://en.wikipedia.org/wiki/Saptarishi
Panini: https://en.wikipedia.org/wiki/Pāṇini
Pravaras: https://en.wikipedia.org/wiki/Pravaras
Gotra: https://en.wikipedia.org/wiki/Gotra
Brahmins: https://en.wikipedia.org/wiki/Brahmin