What is Orochimaru's ancestry? Orochimaru has pale white skin and purple skin around his eyes. His eyes are also similar to that of snakes. Does it signify that he belongs to a particular clan? Or is he one of a kind?
In support of @Quikstryke answer, allow me to elaborate more on this topic.
How Orochimaru gained snake-like characteristics
From Orochimaru article on Naruto Wiki:

Orochimaru was an orphan who became a pupil of Hiruzen Sarutobi alongside Jiraiya and Tsunade. Compared to the more laid back Jiraiya, Orochimaru stood out as a genius — his talents, knowledge, and determination were considered by Hiruzen to be that of a prodigy seen once in a generation. According to Tsunade, Orochimaru had a twisted personality even as a child. His sadistic attitude was presumably due to the death of his parents. At some point after losing them, Orochimaru found a white snake near his parents' grave, with Hiruzen's explanation of it representing fortune and rebirth inspiring Orochimaru to study kinjutsu and obtain knowledge of all techniques. Jiraiya theorised that Orochimaru went down this path in an attempt to forget his painful memories.

From the link above, we learn that Orochimaru did not get his snake like eyes from childbirth, but through his research on the white snake that he found near his parents grave. He spent his life researching about immortality and rebirth.
From Orochimaru article on Wikipedia:

Through his experimentations he has also been able to add some snake-like characteristics to his own body

Orchimaru's Snake Techniques
Below is the list of Orochimaru's snake related techniques.

Orochimaru's trademark trait is his affinity with snakes, in addition to impacting the appearance and composition of his true form, and granting him the ability to extend his limbs to abnormal lengths and to take on snake-like traits in battle, caused him to learn a number of snake-related abilities, including learning Sage Mode. His snake-related techniques have been referred to as Power of the White Snake. One such ability is being able to summon giant snakes to fight alongside him in battle, made possible by the summoning contract tattooed on his arm. This allows him to summon snakes within his vicinity, as opposed to having to place his hand on a surface.
If need be, Orochimaru can morph into a giant snake, despite being slightly smaller in size to his larger ones. His signature summon was Manda, a colossal snake which was described as the largest in the world, with immense fighting capabilities. With Hidden Shadow Snake Hands, Orochimaru can instantly call forth snakes from his sleeves and mouth to attack his opponents in large numbers with venomous bites. A stronger variation of this technique was the Many Hidden Shadow Snake Hands, in which the summoned snakes grow noticeably in both numbers and size.
Another usage of snakes comes in the form of his signature weapon, the Sword of Kusanagi, the Kusanagi of Japanese legend. The sword, kept within the mouth of a snake within his own throat, is able to extend to great lengths to attack enemies that are very far away, can be controlled remotely by Orochimaru, and can return to him by turning in a snake. Although he is capable of wielding the sword normally with great proficiency, it's not uncommon for him to use it without ever removing it from his mouth. The sword is stated to be able to cut through almost anything, and despite failing to penetrate four-tailed Naruto's chakra shroud, did push him back an incredible length. In the anime, he is also capable of having numerous Kusanagi-like blades sprout from the mouths of the snakes he summons.
He is also able to summon use one of his larger snakes around its target, trapping it in its stomach. Following this, Orochimaru can speed up the digestion process on the target. His strongest technique is the Eight Branches Technique, which allows him to transform into an eight-headed, eight-tailed giant serpent bigger than the already colossal Manda, another reference to the Japanese myth. This was described as the ultimate snake-related technique, which turned the user into an immensely powerful &quot;Dragon God&quot;.