( ( ( The longer ) ( ( a ( population group ) ) ( has existed ) ) ) ( , ( ( the ( more diverse ) ) ( ( will ( ( be ( their DNA ) ) ( because ( ( more mutations ) ( will ( have occurred ) ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (X (DT The) (JJR longer)) (S (NP (DT a) (NN population) (NN group)) (VP (VBZ has) (VP (VBN existed))))) (, ,) (NP (DT the) (ADJP (RBR more) (JJ diverse))) (VP (MD will) (VP (VB be) (NP (PRP$ their) (NN DNA)) (SBAR (IN because) (S (NP (JJR more) (NNS mutations)) (VP (MD will) (VP (VB have) (VP (VBN occurred)))))))) (. .)))
The longer a population group has existed, the more diverse will be their DNA because more mutations will have occurred.
(ROOT (S (NP (NNS Mutations)) (VP (VP (VBP are) (NP (NP (NNS changes)) (PP (TO to) (NP (NP (DT an) (NN organism) (POS 's)) (NN dna))))) (CC and) (VP (VBP are) (NP (NP (DT an) (JJ important) (NN driver)) (PP (IN of) (NP (NP (NN diversity)) (PP (IN in) (NP (NNS populations)))))))) (. .)))