[bionet.genome.arabidopsis] thoughts on DNA measurements

KAP2@vaxa.york.ac.uk (04/26/91)

With regard to the enquiry about nuclear DNA measurements
using flow cytometry of leaf cells, it seemed to me that the amount
of chloroplast DNA in leaf cells may be very significant in relation
to the amount in the nucleus so i did a VERY rough calculation.
I know mature Arabidopsis leaf cells have about 120 chloroplasts. assuming the
size of the genome is about 130kB and the copy no per plastid is about 50 ( both

of these values are estimates, others may have accurate values), then there
 would be
6000 copies of chloroplast DNA per mesophyll cell which approximates to about
0.9 pg which is well in excess of published nDNA levels for Arabidopsis. so
using intact cells for nuclear DNA esimates may be very inaccurate. any comments
on  all this would be interesting
regards
kevin pyke
york, england