Siblings with exactly the same parents can have different Ancestry DNA results. It is not compulsory that identical ancestors will give identical ethnicity estimations. In fact, it is common that siblings have different ethnicity results. There are several factors which
If you want to go for Ancestry DNA testing then you can do 3 types of basic DNA testing like Mitochondrial, Autosomal and Paternal testing. You can easily predict your ancestry by these DNAs. Paternal or Y-DNA is very helpful where you want