Mukhopādhyāya and its adaptation Mukherjee are a Kulin brahmin. Mukhopādhyāya means chief Vedic teacher.
The traditional accounts of the origin are given in texts termed Kulagranthas (Kuladīpīkā), composed around the 17th century. They mention a ruler named Ādiśūra who invited five Brahmins from Kanyakubja, so that he could conduct a yajña, because he could not find Vedic experts locally. Traditional texts mention that Ādiśūra was ancestor of Ballāl Sena from maternal side and five brahmins had been invited in AD 1077.
Kulin Brahmins are those Brahmins in Bengal who can trace themselves to the five families of Kanauj (Kanyakubja), Uttar Pradesh who migrated to Bengal. The five families were of the five different gotras (Shandilya, Bharadwaj, Kashyap, Vatsya and Swavarna). They are widely believed to be at the apex of Bengal's caste hierarchy.
Bengali Brahmins showed positive results for only three Y-Haplogroups R1a1, R2 and H1. Haplogroup R1a1, which is the most prevalent haplogroup amongst the Bengali Brahmins, is associated with the spread of the Indo-European culture in Indian sub-continent. A very high percentage of 72.22% among Bengali Brahmins hints at its presence as a founder lineage for this caste group