We expect that siblings have common ancestry results but this is not true. In ancestry results, we should know that our parents have different ancestors and involved many generations. It can happen that brothers or sisters have distinct ancestry results.
Absolutely! We can start with the DNA hereditary trait of the human eye. Ultimately eye color is determined by your ancestral lineage, namely your immediate nucleus. Statistically the paternal side or the father’s side is the dominant source of DNA.