when the conditions of spontaneous mutagenesis are altered , in particular , by cardiovascular diseases in man , by partial inhibition of dna repair in mice and pea cells , by transformation of chinese hamster cells , upon ageing of pea seeds-qualitative changes in the chromosomal aberrations are registered , connected with the appearance of chromosome exchanges and acentric fragments situated within the equatorial plate during metaphase .
C0007634
cells
C0025564
metaphase