A caste is not permanent nor it is a birthright.
A person can change his caste by changing his line of work. If the son of a trader, leaves the profession of trading and becomes a researcher, his status changes to that of a Brahmin. Since Caste is temporary, it has no relevance in performing Pooja’s or rituals
Krishna teaches in the Gita that people are allocated to a specific varna according to two criteria, namely (1) guna (personal qualities) and (2) karma(aptitude for a type of work). He makes no mention of varna being determined by birth.
Sage Vyasa, the most revered author of the “Mahabharata’ was born to a low-caste fisherwoman ‘Satyavati’ and Sage Parasara. Vyasa’s deep knowledge of the Vedas later determined the caste of Vyasa as a Brahmin sage, and not his birth to a low caste woman.
Sage Valmiki, the celebrated author of of the epic ‘Ramayana;, was a low caste hunter. He became a Brahmin sage on the basis of his profound knowledge of the scriptures and his authorship of the Ramayana.
Sage Aitareya, who wrote the Aitareya Upanishad and was born of a Shudra woman.
Rishi Parashar, the famous law giver was the son of a Chandala, the lowest of the Sudras.
Rishi Vasishta , was the son of a prostitute, but honored as a sage.
Sage Vidura, a Brahmin sage who gave religious instructions to King Dhritarashtra, was born to a low-caste woman servant of the palace. His caste as a Brahmin sage was determined on the basis of his wisdom and knowledge of Dharma Shastras (scriptures).
The Kauravas and Pandavas were the descendants of Satyavati, a low caste fisherwoman, and the sons of Sage Vyasa. Vyasa’s father was the Brahmin Sage Parasara, the grandson of Sage Vasishtha. In spite of this mixed heredity, the Kauravas and Pandavas were known as Kshatriyas on the basis of their occupation
Chandragupta Maurya was from the Muria tribe, which used to collect peacock (mor) feathers;Samrat Ashok was the son of a ‘daasi’ (slave). And yet they rose to be emperors ( A Kshatriya) of ancient India.
Saint Thiruvalluvar who wrote Thirukural was only a weaver (lower-caste). Other saints were adored including Kabir, Sura Dasa, Ram Dasa and Tukaram came from the humblest class of Hindu society. And all of them rose to be saints.