DNA testing can determine if your brother, sister, father or mother are your true biological ones.
father
Your grandfather.
If your mother and her brother share the same parents, then her brother's father would be considered your grandfather
Your mother's brother's brother-in-law could be your father or unrelated to you
Your father's brother is your uncle. English does not have different names for a father's elder and younger brother. If you are a boy, you are your uncle's nephew; if you are a girl, you are his niece.
Mother Father Brother Sister was created on 1998-06-24.
In most cases, your brother's father is also your father. If your brother is actually your half-brother, and you have the same mother, then your brother's father is either your stepfather or is not related to you at all.
When your aunt is your aunt because she married your father's brother, her mother is not related to you.
Mother's brother: Mama Father's brother or Mother's sister's husband or Father's sister's husband: Kaka
Your uncle is the brother of your mother or your father - or the husband of the sister of your mother or your father.
If your older brother impregnated his (and your) mother.
Your baby brother's mother and father did.