Caitanya Mahaprabhu's ancestors

Bhavabhuti Dasa: In the fall of 1976, after Prabhupada became a little sick in Bombay, he was not taking his morning walks on the beach any more. He was taking them on the rooftop. I asked Srila Prabhupada why so many people from the Northeast area of India were wearing Vaisnava tilaka. Prabhupada replied that Caitanya Mahaprabhu's ancestors were from Assam, which is now in Bangladesh. So why not?