Yup. ALL of the early RPGs are "direct descendants" of D&D in that sense. Traveller fell considerably farther from the tree than nearly any other in that first generation, though.
I'd argue that RuneQuest actually falls further...
| RQ | D&D | Traveller |
| 7 attributes, (STR CON SIZ INT POW DEX CHA) | 6 atts (Str Int Wis Con Dex Cha | 6 atts Str Dex End Int Edu Soc |
| 3d6 | 3d6 | 2d6 |
| To-Hit and Armor Penetration separated (armor reduces damage) | To-hit and Pen combined | to Hit and Pen Combined; Striker/AHL separates it in the 80's |
| Totally classless | Class & Level | Class but not level |
| clear opposed roll mechanics | No opposed roll mechanics | No opposed roll mechanic |
| coupled to a setting from the get go | No setting and only weak setting implications | fairly strongly implied setting in core, explicit setting in later editions |
| large format | small format | small format |
| Reliant on d10's & d6's | d10's optional* d6's required | d6 only |
| Hit Locations matter | No hit locations | No Hit Locations |
| Fantasy | Fantasy | Sci-Fi |
Setting wise, Traveller's quite different; mechanically, RQ is more distant. (And a year later).