Passed down directly from new alien vessel's base (6)
I believe the answer is:
lineal
'passed down directly' is the definition.
I can't tell whether this definition defines the answer.
'new alien vessel's base' is the wordplay.
'new' indicates anagramming the letters.
'base' says to take the final letters (the base of the word).
The final letter of 'vessel' is 'l'.
'alien' is an anagram of 'linea'.
'linea'+'l'='LINEAL'
'from' acts as a link.
Can you help me to learn more?
(Other definitions for lineal that I've seen before include "Transmitted by direct descent" , "In a straight row" , "In line of descendants" , "In a line as, say, a descendant" , "In a direct line of descent" .)