( ( For ( ( ( a human ) , ) ( ( a mutation ) ( in ( ( a ( single gene ) ) containing ) ) ) ) ) ( , ( ( ( ( e.g. , ) ( 1000 bases ) ) , ) ( ( might ( take ( thousands ( of generations ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN For) (NP (NP (DT a) (NN human)) (, ,) (NP (NP (DT a) (NN mutation)) (PP (IN in) (NP (NP (DT a) (JJ single) (NN gene)) (VP (VBG containing))))))) (, ,) (NP (NP (NNP e.g.)) (, ,) (NP (CD 1000) (NNS bases)) (, ,)) (VP (MD might) (VP (VB take) (NP (NP (NNS thousands)) (PP (IN of) (NP (NNS generations)))))) (. .)))
For a human, a mutation in a single gene containing, e.g., 1000 bases, might take thousands of generations.
(ROOT (S (NP (DT A) (JJ single) (JJ human) (NN body) (NN cell)) (ADVP (RB typically)) (VP (VBZ contains) (NP (NP (NNS thousands)) (PP (IN of) (NP (NNS genes))))) (. .)))
A single human body cell typically contains thousands of genes.