I think two of the major themes that can be identified in this impressive text is the theme of coming of age and then the theme of human rights. Critics have argued that the first section of this text is essentially a coming-of-age tale as Kunta Kinte goes through a series of experiences which teach him how to be an adult. The way he is instructed as a young child by hearing stories that teach him his place in the world is focused on, as is the formal period of training that he undergoes to be a man and going through a rite of passage that enables him to have the symbols of manhood: his own farm and hut.
However, tragically, being sold into slavery means that Kunta has to repeat this process, but in a very different context, as he learns a new langauge and culture. However, being a slave means that you are never able to become an adult. Kunta is trapped in the role of a child as he is subject to the whims and desires of those above him and is not given the opportunity to take responsibility for his own actions.
Also, this text is above all about human dignity and human rights. The overwhelming message of this narrative is the way in which slavery and human rights are mutually exclusive. Most poignantly this is shown in the way in which family members are sold without respect for family relations as is shown when the daughter of Kunta and Bell is sold against their wishes. It is in such scenes that the ultimate cruelty and demeaning attitude of treating humans as disposable bits of property is revealed. The way in which sold slaves have no further links with their families is very disturbing, and the irony of this is shown in the way that Master Waller, who is depicted as a fair master, can get Kunta to take him to see his family whenever he wants, but when he sells Kizzy, Kunta knows that he will never be able to see her again. The threat of separation and the way it disturbingly lurks around the central characters reinforces the basic lack of dignity and rights that is associated with slavery.