Rud a bheith ionnat ó duthchas. = What you inherited, .i. as regards nature etc. not something got by inheritance. Thá sé ó dhúthchas ins na Tóibínig a bheith crom-shlinneánach. Briseann an dúthchas trí shúile an chait.
Rud athá i nduine ó dhúthchas - heredity. Thá an ghadaidheacht ann ó dhúthchas. = Being a thief is hereditary in him. Sprionnlóir iseadh é ó dhúthchas.