Complex sentence: The Guinness family, though Protestants, claimed descent from the Magennis Gaelic Catholic clan of County Down in the 1600s, but recent DNA evidence instead suggests descent from the McCartans, another County Down clan.
Split into simpler sentences: The Guinness family, though Protestants, claimed descent from the Magennis Gaelic Catholic clan of County Down in the 1600s. Recent DNA evidence instead suggests descent from the McCartans, another County Down clan.