Genetic Recombination="Is the production of offspring with combinations of traits that differ from those in either parent."
You may not have the same ethnicity as your brothers sisters. Your children may not have the same as you. A brother might have some Jewish DNA and his sister not. DNA is random.
If you think yours is wrong you might try a different company. FTDA seems to be more general than Ancestry.
jbarry 6899 is correct. This is a discussion board for members. Contact Ancestry if you believe they made a error.
Mike