( ( ( The mechanisms ) ( that ( lead ( to ( chromosomal abnormalities ) ) ) ) ) ( ( ( have ( their roots ) ) ( in ( ( meiosis , ) ( ( the formation ) ( of ( ( sperm and ) egg ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NNS mechanisms)) (SBAR (WHNP (WDT that)) (S (VP (VBP lead) (S (VP (TO to) (VP (VB chromosomal) (NP (NNS abnormalities))))))))) (VP (VBP have) (NP (PRP$ their) (NNS roots)) (PP (IN in) (NP (NP (NNS meiosis)) (, ,) (NP (NP (DT the) (NN formation)) (PP (IN of) (NP (NN sperm) (CC and) (NN egg))))))) (. .)))
The mechanisms that lead to chromosomal abnormalities have their roots in meiosis, the formation of sperm and egg.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (DT a) (NN sperm)) (VP (VBZ penetrates) (NP (DT the) (NN egg))))) (, ,) (NP (PRP it)) (VP (VBZ triggers) (NP (DT the) (NN egg) (S (VP (TO to) (VP (VB complete) (NP (NNS meiosis))))))) (. .)))