marriage in same gotra
Both Manu as well as Matsya Purana prohibit marriage with sapinda relatives on the mother's side and sagotra relatives on the father's side.
Quoted in Dharmakosa -
असपिण्डा या मातुरसगोत्रा च या पितुः /
सा प्रशस्ता द्विजातीनां दारकर्मणि मैथुने //
Dharmakosa, pub. Prajna pathasala mandal, Wai, Satara. III.1.p.177 ff
Both Manu as well as Matsya Purana prohibit marriage with sapinda relatives on the mother's side and sagotra relatives on the father's side.
Quoted in Dharmakosa -
असपिण्डा या मातुरसगोत्रा च या पितुः /
सा प्रशस्ता द्विजातीनां दारकर्मणि मैथुने //
Dharmakosa, pub. Prajna pathasala mandal, Wai, Satara. III.1.p.177 ff