these include mistakes in dna synthesis by an error-prone dna polymerase , the nucleotide pool distartion and the overreplication of replication origins , abnormal dna repair , high rate recombination , by expression of fragile sites and possibly by expression of retrotransposons , frequent nondisjunction of chromosomes as a consequence of gene dosage inbalance , and abnormal dna methylation .
C0242961
of replication origins
C0008633
chromosomes