Changing Hair Texture

Hi, my name is Trudi and recently my hair texture has started to change. I was born with extremely kinky hair (I'm African American by the way). In fact, it was way more kinky than your average AA's hair texture and EXTREMELY difficult to comb. Recently, my hair has started thinning a little. Now my hair is starting to grow in curlier, like this: http://en.wikipedia.org/wiki/Image:Afro_by_David_Shankbone.jpg).
The only reason I could think of that caused this change is that I perm my hair. Is this a valid reason?
Just to make you now: My mother had a weird hybrid between straight and kinky hair (it wasn't curly though) and my older brother has the same hair type. On the other hand, my dad has kinky hair as well, along with my younger brother. Could this be my mothers genes coming into play or is the change in my hair texture due to another reason, like my hormones? Thanks in advance!!!