( ( Crossing ( Over ( crossing over ) ) ) ( , ( ( process ( in ( genetics ( ( by which ) ( ( ( the ( two chromosomes ) ) ( of ( a ( homologous ( pair exchange ) ) ) ) ) ( ( equal segments ) ( with ( each other ) ) ) ) ) ) ) ) . ) ) )
(ROOT (S (PP (NP (NN Crossing)) (IN Over) (S (VP (VBG crossing) (PRT (RP over))))) (, ,) (VP (VB process) (PP (IN in) (NP (NP (NNS genetics)) (SBAR (WHPP (IN by) (WHNP (WDT which))) (S (NP (NP (DT the) (CD two) (NNS chromosomes)) (PP (IN of) (NP (DT a) (RB homologous) (NN pair) (NN exchange)))) (VP (VBP equal) (NP (NNS segments)) (PP (IN with) (NP (DT each) (JJ other))))))))) (. .)))
Crossing Over crossing over, process in genetics by which the two chromosomes of a homologous pair exchange equal segments with each other.
(ROOT (S (NP (NP (NNP Exchange)) (PP (IN of) (NP (NN dna) (NNS segments)))) (VP (VBZ happens) (PP (IN between) (NP (NP (JJ non-sister) (NNS chromatids)) (PP (IN of) (NP (NP (RB homologous) (NNS chromosomes)) (PP (IN during) (NP (NN crossing-over)))))))) (. .)))