My sister and I are half-siblings. We have always know this and my mother reportedly had an affair during WW2. This was confirmed with ancestry DNA as we only share 1603cM.
I'm trying to filter out matches that could be on my paternal side. I have a match with someone who I share 475cM with. They are not dNA matched to my sister.
Would it be possible to still be related to this person via my half-sister/Mum as we can inherit different DNA even if we were full siblings or would sharing as much as 475cM across 23 segments only possible via a different paternal side?