Bethóc ingen Maíl Coluim meic Cináeda was the eldest daughter of Máel Coluim mac Cináeda, King of Scots, who had no known sons.
Princess Bethóc married Crínán, Abbot of Dunkeld. The first son of this marriage was Donnchad I, who ascended to the throne of Scotland in 1034. Early writers have asserted that Máel Coluim also designated Donnchad as his successor under the rules of tanistry because there were other possible claimants to the throne.
In this period, the Scottish throne still passed in Picto-Gaelic matrilineal fashion, from brother to brother, uncle to nephew, and cousin to cousin. Duncan I's accession is thus noteworthy for being the beginning the transition to the evolving Anglo-Norman system of primogeniture (wikipedia)