Isn't Sorcerer Origin and race kind of overlap somewhat. I mean how different in nature is a Good Affinity Divine Soul and an Aasimar or a Evil/Lawful Affinity Divine Soul and a Tiefling? Dragonborn and Dragonblooded Sorcerer?
Avoiding any touchy real world tie ins - i tend to see sorcerer as a case where the link is much more a magical manifestation than a physical issue of genetics and chemistry. more a manifestation of the "power" than the form.
in a comics sense - rough and vague correlation - more hulk or spider-man than Cyclops or Iceman - just maybe some generations removed.
So that means the "family tree" of a sorcerer is highlighted by exceptional things within their own "community of insert race here) while the family tree of dragonborn might well be unremarkable for a dragonborn community.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.