Muladhara or root chakra is represented as a yellow square, with 4 red petals. The seed syllable is Lam, the deity is Ganesh, and the Shakti is Dakini. The associated animal is the elephant Ganesha. This chakra is where the 3 channels are merged, then separate and begin their upward movement. Inside of this chakra is wrapped up the goddess kundalini three times around a black lingam. It is the seat of the red bindu, the female drop (which in Tibetan vajrayana is located at the navel chakra).
Muladhara is related to instinct, security, survival and also to basic human potentiality. This center is located in the perineum, which is the region between the genital and the anus. Although no endocrine organ is placed here, it is said to relate to the gonads and the adrenal medulla, responsible for the fight-or-flight response when survival is under threat. There is a muscle located in this region that controls ejaculation in the sexual act of the human male. A parallel is charted between the sperm cell and the ovum where the genetic code lies coiled and the kundalini. Muladhara is symbolized by a lotus with four petals and the colour red. Key issues involve sexuality, lust and obsession. Physically, Muladhara governs sexuality, mentally it governs stability, emotionally it governs sensuality, and spiritually it governs a sense of securityThere is no chakra that exists in this position within Tibetan buddhism. Instead, below the secret place wheel, there are 2 other wheels, the jewel wheel, which is located in the middle of the sex organ, and the wheel located at the tip of the sex organ. These wheels are extremely important for the generation of great bliss, and are involved with tantric consort practices.
Source - Wikipedia