Advanced Bloodline (Kekkei Genkai) is an ability, which is only passed down genetically through a specific clan, and can only be inherited through blood. The only way to copy the Advanced Bloodline is to genetic manipulation or organ transplantation.
Most rulers of a nation have taken advantage of shinobis with the Advanced Bloodline ability, for there own war and reputation. It eventually reached to the point of fear and hatred, which then resulting in witch hunts of families and individuals with the Advanced Bloodline ability.
Byakugan
Clan: Hyuuga Clan
Country: Fire Country, Hidden Leaf Village
Description: The Byakugan is a special pupil, which only occurs in members of the Hyuga clan. The Byakugan users have a pupil less eye, but once the Byakugan is active the pupil appears and veins near there temple.
Hyoton
Clan: Unknown Clan (Haku)
Country: Water Country, Hidden Mist Village
Description: Not much is know about this clan, the clan name is also unknown and it appears that Haku was the only living member of this clan. He is able to combine wind and water based chakra to create ice.
Sharingan
Clan: Uchiha Clan
Country: Fire Country, Hidden Leaf Village
Description: The Sharingan is a special type of pupil, which only occurs in some members of the Uchiha clan. It is believed that the Sharingan is the evolved from of the Byakugan, with many different abilities, like able to memorize nijutsu, genjutsu and taijutsu techniques, which has been witnessed.
Shikotsumyaku
Clan: Kaguya Clan
Country: Sound Country, Hidden Sound Village
Description: The Kaguya clan, have the ability to manipulate their own skeletal structure, they also have free control over the cells, which are responsible for bone growth and replacement, allowing them to manipulate their bones at their own will.